Glossary
A
active statement An SQL statement that has been executed but whose result set has not yet been canceled or fully processed. When using default result sets, Microsoft SQL Server supports only one active statement at a time on a connection. ODBC and OLE DB_based applications support multiple active statements on a SQL Server connection when using application programming interface (API) server cursors.
add-in A custom extension, written in any language that supports the component object model (COM), usually Microsoft Visual Basic, that interacts with the OLAP Manager and provides specific functionality. Add-ins are registered with the online analytical processing (OLAP) Add-In Manager. They are called by the OLAP Add-In Manager in response to user actions in the user interface.
ad hoc connector name A connector name used for infrequent queries against OLE DB data sources that are not defined as linked servers. The OpenRowset function in the FROM clause of a query, which allows all connection information for an external server and data source to be issued every time the data must be accessed, provides the properties and parameters necessary to access specific data.
ADO MD See Microsoft ActiveX Data Objects (Multidimensional) (ADO MD).
aggregate functions Functions that calculate summary values, such as averages and sums, from the values in a particular column and return a single value for each set of rows to which the function applies. The aggregate functions are AVG, COUNT, COUNT(*), MAX, MIN, SUM, STDEV, STDEVP, VAR, and VARP. Aggregate functions can be applied either to all rows in a table, to a subset of table rows specified by a WHERE clause, or to one or more groups of table rows specified by the GROUP BY clause.
aggregate query A query that summarizes information from multiple rows by including an aggregate function such as SUM or AVG. Aggregate queries that use the GROUP BY clause can also display subtotal information by creating groups of rows that have data in common.
aggregation A table or structure containing precalculated data for a cube. Aggregations support rapid and efficient querying of a multidimensional database. See precalculate.
aggregation prefix A string that is combined with a system-defined ID to create a unique name for a partition's aggregation table. A default string is generated based on the name of the partition and the name of its parent cube, but a user-defined string of up to 21 characters can be specified to replace the automatically generated string.
alert A user-defined response to a SQL Server event. Alerts can either execute a defined task or send an e-mail and/or pager message to a specified operator.
alias In structured query language, an alternate name for a table or column in expressions that is often used to shorten the name for subsequent reference in code, prevent possible ambiguous references, or provide a more descriptive name in query output. In SQL Server 6.5, a database username shared by several login IDs. In SQL Server 7, aliases have been replaced by roles.
All level The optional highest level of a dimension, named "(All)" by default. The All level contains a single member that is the summary of all members of the immediately subordinate level.
allocation page See Global Allocation Map (GAM).
allocation unit See Global Allocation Map (GAM).
American National Standards Institute (ANSI) An organization of American industry and business groups that develops trade and communication standards for the United States. Through membership in the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), ANSI coordinates American standards with corresponding international standards. ANSI published the ANSI SQL-92 standard in conjunction with the ISO/IEC SQL-92 standard.
ancestor A member in a superior level in a dimension hierarchy that is related through lineage to the current member within the dimension hierarchy. For example, in a Time dimension containing the levels Quarter, Month, Day, Qtr1 is an ancestor of January 1. See child; descendant; parent; sibling.
anonymous subscription A pull subscription that allows a server known to the Publisher only for the duration of the connection to receive a subscription to a publication. Anonymous subscriptions require less overhead than standard pull subscriptions because information about them is not stored at the Publisher or the Distributor.
ANSI See American National Standards Institute (ANSI).
ANSI SQL-92 See SQL-92.
ANSI to OEM conversion Conversion behavior when you connect to a server, controlled by an operating system option, AutoANSItoOEM. If ON (the default), conversion occurs in these cases:
The DB-Library Automatic ANSI to OEM option converts characters from OEM to ANSI when communicating with SQL Server, and from ANSI to OEM when communicating from SQL Server to the client. You can set Automatic ANSI to OEM by using the SQL Server Client Network Utility.
API See application programming interface (API).
API server cursor A server cursor built to support the cursor functions of an application programming interface (API), such as ODBC, OLE DB, ADO, and DB-Library. An application does not usually request a server cursor directly; it calls the cursor functions of the API. The SQL Server interface for that API implements a server cursor if that is the best way to support the requested cursor functionality.
application log A Windows NT file that records events. It can be viewed only by using Windows NT Event Viewer. When SQL Server is configured to use the Windows NT application log, each SQL Server session writes new events to that log. (Unlike the SQL Server error log, a new application log is not created each time you start SQL Server.)
application programming interface (API) A set of routines available in an application, such as DB-Library, for use by software programmers when designing an application interface.
application role A SQL Server role created to support the security needs of an application. Such a role is activated by a password and the use of the sp_setapprole system stored procedure.
argument A switch supported by a function that allows you to specify a particular behavior. Sometimes called an option or a parameter.
article The basic unit of replication. An article contains data originating from a table or stored procedure marked for replication. One or more articles are contained within a publication.
attribute A qualifier of an entity or a relation describing its character quantity, quality, degree, or extent. In database design, tables represent entities and columns represent attributes of those entities. For example, the title column represents an attribute of the entity titles.
authentication The operation that identifies the user and verifies the permission to connect with SQL Server.
authorization The operation that verifies the permissions and access rights granted to a user.
automated server restart If SQL Agent detects that the SQL Server service has stopped unexpectedly, it will automatically attempt to restart SQL Server. This automated restart behavior can be adjusted by modifying properties in the SQL Server Agent Properties sheet.
automatic recovery Recovery that occurs every time SQL Server is restarted. Automatic recovery protects your database if there is a system failure. In each database, the automatic recovery mechanism checks the transaction log. If the log has committed transactions that have not been written to the database, it performs those transactions again. This action is known as rolling forward. If the log has uncommitted transactions that have not been written to the database, it removes those transactions from the log. This action is known as rolling back.
automatic synchronization Synchronization that is accomplished automatically by SQL Server when a server initially subscribes to a publication. A snapshot of the table data and schema are written to files for transfer to the Subscriber. The table schema and data are transferred by the distribution agent. No operator intervention is required.
auto-start options The Setup program can configure the SQL Server and SQL Agent services to run as an automatically started service. For each service, this choice is called the autostart option.
axis A set of tuples. Each tuple is a vector of members. A set of axes defines the coordinates of a multidimensional dataset. For more information about axes, see your OLE DB documentation. See also slice; tuple.
B
B-tree Balanced tree. This term describes SQL Server index structures.
back end A term applied to the database server level where processing, data storage, and data retrieval occur.
back up To create a copy of a database, transaction log, file, or filegroup in a database on another device or file. A backup is made to tape, named pipe, or hard disk. Backups are made using either SQL Server Enterprise Manager or the BACKUP statement.
backup device A tape, disk file, or named pipe used in a backup or restore operation.
backup domain controller (BDC) In a Windows NT domain, a server that receives a copy of the domain's security database from the primary domain controller (PDC) and shares the user login authentication load.
backup file A file that stores a full or partial database, transaction log, or file and/or filegroup backup.
backup media The disk, tape, or named pipe used to store the backup set.
backup set The output of a single backup operation.
base data type Any system-supplied data type—for example, char, varchar, binary, and varbinary—from which user-defined data types are made.
base object See underlying object.
base table A table from which a view is derived. Also called an underlying table. A view can have one or more base tables or base views.
batch A set of SQL statements submitted together and executed as a group. A script is often a series of batches submitted one after the other. A batch, as a whole, is compiled only one time and is terminated by an end-of-batch signal (such as the GO command in SQL Server utilities).
bcp See bulk copy program (bcp).
bcp files Files that have been exported from SQL Server through bcp. Though not required, native bcp files usually have a .BCP extension, and character bcp files customarily have a .TXT extension. During replication synchronization, the .SCH and .BCP files are a synchronization set that represents a snapshot in time of an article.
bcp utility See bulk copy program (bcp)
binary data type A data type storing hexadecimal numbers. The binary data type can contain 0 bytes, but when specified, n must be a value from 1 through 8000. Storage size is n regardless of the actual length of the entry.
binding In SQL application programming interfaces (APIs), associating a result set column with a program variable so that data is moved automatically into or out of a program variable when a row is fetched or updated. In Transact-SQL, associating rules or defaults with table columns by using sp_bindrule or sp_bindefault.
bit data type A data type that holds a value of either 1 or 0. Integer values other than 1 or 0 are accepted but interpreted as 1. The storage size is 1 byte. Multiple bit data types in a table can be collected into bytes. Use bit for true/false or yes/no data.
BLOB (binary large object) A type of data column containing binary data such as graphics, sound, or compiled code. This is a general term for text or image data type. BLOBs are not stored in the table rows themselves, but in separate pages referenced by a pointer in the row.
blocks A series of statements enclosed by BEGIN and END. Blocks define which set of statements will be affected by control-of-flow language such as IF or WHILE. You can nest BEGIN...END blocks within other BEGIN... END blocks.
Books Online See SQL Server Books Online.
Boolean expression An expression that returns a true or false value. For example, comparing the value 1 to the value 5 returns a false value (1=5). WHERE clauses are boolean expressions.
broken ownership chain See ownership chain.
browse mode A function that lets you scan database rows and update their values one row at a time. Several browse mode functions return information that an application can use to examine the structure of a complicated ad hoc query.
buffer cache The pool of buffer pages into which data pages are read.
built-in functions A group of functions provided by SQL Server and grouped as follows:
bulk copy program (bcp) A command-line utility that copies SQL Server data to or from an operating system file in a user-specified format.
BULK INSERT A Transact-SQL command for importing external data into SQL Server tables.
business rules An organizational standard operating procedure that requires that certain policies be followed to ensure that a business is run correctly. Business rules ensure that the database maintains its accuracy with business policies. SQL Server can use defaults, rules, triggers, and stored procedures to ensure that data adheres to business rules.
C
cache A buffer used to hold data during input/output (I/O) transfers between disk and random access memory (RAM). See also buffer cache.
cached pages Pages that are held in cache. One page is 8 KB of data.
calculated member A member of a dimension whose value is calculated at run time using an expression. Calculated member values may be derived from other members' values. A calculated member is any member that is not an input member. For example, a calculated member Profit can be determined by subtracting the value of the member Costs from the value of the member Sales. See also Calculated Member Builder; input member.
Calculated Member Builder A dialog box in the OLAP Manager used to create calculated members. You can pick parent members and members from a list. In addition, you can construct calculated value expressions using the cube data and analytical functions provided. See also calculated member.
call-level interface (CLI) The interface supported by ODBC for use by an application.
candidate key A unique identifier for a row within a database table. A candidate, or surrogate, key can be made up of one or more columns. In a normalized database, every table must have at least one candidate key, in which case it is considered the primary key for a table automatically. However, it is possible for a table to have more than one candidate key, in which case one of them must be designated as the primary key. Any candidate key that is not the primary key is called the alternate key.
capture The process of recording and storing information during the monitoring process.
Cartesian product All of the possible combinations of the rows from each of the tables involved in a join operation. The number of rows in a Cartesian product of two tables, for example, is equal to the number of rows in the first table multiplied by the number of rows in the second table. Cartesian products almost never provide useful information. Queries using the CROSS JOIN clause or queries without enough JOIN clauses create Cartesian products.
cascading delete A delete operation that deletes all related database rows or columns. Cascading deletes are typically implemented using triggers or stored procedures.
cascading update An update operation that updates all related database rows or columns. Cascading updates are typically implemented using triggers or stored procedures.
catalog (database) See database catalog.
catalog (full-text) Full-text indexes are contained in full-text catalogs. Each database can use one or more full-text catalogs. Full-text catalogs and indexes are not stored in the database to which they belong. The catalogs and indexes are managed separately by the Microsoft Search service.
catalog (system) See system catalog.
cell In a relational database, the addressable attribute of a row and column. In a cube, the set of properties, including a value, specified by the intersection when one member is selected from each dimension. See also coordinate.
change script A text file that contains SQL statements for all changes made to a database, in the order in which they were made, during an editing session. Each change script is saved in a separate text file with an .SQL extension. Change scripts can be applied back to the database later, using a tool such as isql.
character See char(n) data type.
character format Data stored in a bulk copy data file using text characters.
character set A set that determines the types of characters that SQL Server recognizes in the char, varchar, and text data types. A character set is a set of 256 letters, digits, and symbols specific to a country or a language. The printable characters of the first 128 values are the same for all character sets. The last 128 characters, sometimes referred to as extended characters, are unique to each character set. A character set is related to, but separate from, Unicode characters. A character set is also referred to as a code page.
char(n) data type A character data type that holds a maximum of 8000 characters. Storage size is n regardless of the actual length of the entry. The SQL-92 synonym for char is character.
CHECK constraints Constraints that specify data values that are acceptable in a column. You can apply CHECK constraints to multiple columns, and you can apply multiple CHECK constraints to a single column. When a table is dropped, CHECK constraints are also dropped.
checkpoint The point at which all changed data pages from the buffer cache are written to disk.
child In OLAP Services, a member in the next lower level in a hierarchy that is directly related to the current member. For example, in a Time dimension containing the levels Quarter, Month, and Day, January is a child of Qtr1. In referential integrity, the term "child" is sometimes used to describe the "many" table in a parent/child, or one-to-many, relationship. See also ancestor; descendant; parent; sibling.
CLI See call-level interface (CLI).
client A front-end application that uses the services provided by a server. The computer that hosts the application is referred to as the client computer. SQL Server client software enables computers to connect to a computer running SQL Server over a network.
client application In OLAP Services, an application that retrieves data from an OLAP server and performs local analysis and presentation of data from relational or multidimensional databases. Client applications connect to the OLAP server through the PivotTable Service component. See also PivotTable Service. In client/server computing, see also client.
client cursor A cursor implemented on the client. The entire result set is first transferred to the client, and the client application programming interface (API) software implements the cursor functionality from this cached result set. Client cursors typically do not support all types of cursors, only static and forward-only cursors.
client/server computing A system of computing in which two or more computers share processing across a network. The server computer manages a shared resource, such as a database, and responds to requests from clients for use of this resource. The client computer interacts with a user and makes requests for use of a shared resource. Client/server computing separates the functions of an application into two parts: a front-end component and a back-end component. The client presents and manipulates data on the workstation; the server stores, retrieves, and protects data.
clustered index An index in which the logical or indexed order of the key values is the same as the physical stored order of the corresponding rows that exist in a table.
clustering The use of multiple computers to provide increased reliability, capacity, and management capabilities.
code page See character set.
collection (COM) A group of objects of the same type contained within a parent object. For instance, in SQL-DMO, the Database object exposes a Tables collection. See also SQL-DMF.
column In a SQL database table, the area, sometimes called a field, in each row that stores the data about an attribute of the object modeled by the table (for example, the ContactName column in the Customers table of the Northwind database). Individual columns are characterized by their maximum length and the type of data that can be placed in them. A column contains an individual data item within a row.
column-level constraint A restriction used to enforce data integrity on a column. SQL Server provides these types of constraints: CHECK, DEFAULT, FOREIGN KEY REFERENCE, PRIMARY KEY, and UNIQUE. See also table-level constraint.
COM See component object model (COM).
commit A statement used to complete a transaction begun with a BEGIN TRAN statement, which guarantees that either all or none of the transaction's modifications are made a permanent part of the database. A COMMIT statement also frees resources, such as locks, used by the transaction. See also roll back.
common key A key created to make explicit a logical relationship between two tables in a database. See also foreign key (FK); primary key (PK).
complex relationship A relationship among more than two entities, subsets, dependencies, or relations.
component object model (COM) The programming model on which several SQL Server and database application programming interfaces (APIs), such as SQL-DMO, OLE DB, and ADO, are based.
composite index An index that uses more than one column in a table to index data.
composite key A key composed of two or more columns. A drawback of composite keys is that they require more complex joins when two or more tables are joined.
COM-structured storage file A component object model (COM) compound file consisting of a root storage object containing at least one stream object representing its native data, along with one or more storage objects corresponding to its linked and embedded objects. The root storage object maps to a filename in whatever file system it happens to reside.
concatenation Combining two or more character strings or expressions into a single character string or expression, or combining two or more binary strings or expressions into a single binary string or expression.
concurrency A process that allows multiple users to access and change shared data at the same time. SQL Server uses locking to allow multiple users to access and change shared data at the same time without conflicting with one another.
concurrency control The control of concurrent access. SQL Server uses locking to allow multiple users to access and change shared data at the same time without conflicting with one another.
concurrent access Occurs when more than one user accesses and updates shared data at the same time.
connection A successful login to a computer running SQL Server. A connection occurs through an interprocess communication mechanism such as named pipes between the client application and SQL Server.
connectivity The ability of different classes of computers to communicate with one another.
console tree In Microsoft Management Console, the left-hand panel is known as the console tree. Highlighting objects in the console tree will determine which details are shown in the details pane, which is the right-hand panel. See also details pane.
console utility The console command-prompt utility displays backup and restore messages when backing up to or restoring from tape dump devices, and is used by the person responsible for backing up and restoring a database.
constant Any constant or literal string, built-in function, or mathematical expression. The value cannot include the names of any columns or other database objects.
constant expression An expression that contains only constant values (it does not include the names of any columns or other database objects). You can use any constant, built-in function, mathematical expression, or global variable. The default value must be compatible with the data type of the column.
constant value See constant.
constraint A property that can be placed on a column or set of columns in a table. SQL Server provides these constraints: CHECK, DEFAULT, FOREIGN KEY, REFERENCE, PRIMARY KEY, and UNIQUE.
continuation media The media inserted when the initial medium becomes full, allowing continuation of the backup operation.
control-break report A report whose summary values are controlled by user-defined groupings or breaks.
control file See master database.
controlled access protocols Protocols that control the access that Subscribers have to a publication by marking the publication as either unrestricted or restricted.
control-of-flow language Transact-SQL keywords that control the flow of execution of SQL statements, statement blocks, and stored procedures. IF and WHILE are examples of control-of-flow language.
conversion function See type conversion function.
coordinate An element (member or tuple) of an axis. The intersection of a set of coordinates determines a cell. See also cell.
correlated subquery A repeating subquery. Many queries can be evaluated by executing the subquery once and substituting the resulting value or values into the WHERE clause of the outer query. In queries that include a correlated subquery, the subquery depends on the outer query for its values. This means that the subquery is executed repeatedly, one time for each row that is selected by the outer query.
covering index A nonclustered index that contains all of the columns required to satisfy a query, in both the selection list and the WHERE clause.
CPU busy A SQL Server statistic that reports the time, in milliseconds, that the central processing unit (CPU) spent on SQL Server work. CPU busy is reported as part of the sp_monitor output.
creation script A script that contains CREATE statements. In SQL Enterprise Manager and replication, an option that adds object-creation statements to a script.
cube A subset of data, usually constructed from a data warehouse, that is organized and summarized into a multidimensional structure defined by a set of dimensions and measures. A cube's data is stored in one or more partitions.
Cube editor A tool in the OLAP Manager that you can use to create new cubes or edit existing ones.
cube file See local cube.
cursor A database object used by applications to manipulate data by rows instead of by sets. Using cursors, multiple operations can be performed row by row against a result set with or without returning to the original table. In other words, cursors conceptually return a result set based on tables within the database(s). For example, a cursor can be generated to include a list of all user-defined table names within a database. After the cursor has been opened, movement (fetching) through the result set can include multiple operations against each table by passing each table name as a variable. Cursors are powerful when combined with stored procedures and the EXECUTE statement (to build strings dynamically). Cursors are a powerful component of the SQL Server application programming interfaces (APIs).
cursor library A part of the ODBC and DB-Library application programming interfaces (APIs) that implements client cursors. A cursor library is not commonly used in current systems; server cursors are used instead.
D
data The coded representation of information for use in a computer. Data has attributes, such as type and length.
database A collection of information, tables, and other objects organized and presented to serve a specific purpose, such as facilitate searching, sorting, and recombining data. Databases are stored in files.
database catalog The set of system tables in a database that describes the database contents. See also system catalog.
Database Consistency Checker (DBCC) A statement used to check the logical and physical consistency of a database, check memory usage, decrease the size of a database, check performance statistics, and so on. Database Consistency Checker (DBCC) ensures the physical and logical consistency of a database and can repair certain database errors.
database diagram A graphical representation of any portion of a database schema. A schema is a description of a database to the database management system (DBMS), generated using the data definition language (DDL) provided by the DBMS. A database diagram can be either a whole or a partial picture of the structure of a database; it includes objects for tables, the columns they contain, and the relationship between them.
database file A file in which a database is stored. One database can be stored in several files.
database language The language used for accessing, querying, updating, and managing data in relational database systems. SQL is a widely used database language. With SQL, you can retrieve data from a database, create databases and database objects, add data, modify existing data, and perform other complex functions. Many of these capabilities are implemented by using one of three types of SQL statements: data definition language (DDL), data manipulation language (DML), and data control language (DCL). The Microsoft SQL Server implementation of SQL is called Transact-SQL.
database management system (DBMS) A repository for the collection of computerized data files that enables users to perform a variety of operations on those files, including retrieving, appending, editing, updating, and generating reports.
database name A name given to a database. Database names must be unique within a server and conform to the rules for identifiers. They can be up to 128 characters.
database object One of the components of a database: a table, index, trigger, view, key, constraint, default, rule, user-defined data type, or stored procedure.
database object owner A user who creates a database object (table, index, view, trigger, or stored procedure) and is automatically granted all permissions on it. The middle section of a fully qualified object name identifies the database object owners. For example, northwind.dbo .customers.
database owner A member of the database administrator role of a database. There is only one database owner, although multiple people can be assigned the role of db_owner. The owner is usually the database creator and has full permissions in that database and determines the access and capabilities provided to other users.
database query See query.
database script A collection of statements used to create database objects. Transact-SQL scripts are saved as text files, usually ending with .SQL.
database verification utility See Database Consistency Checker (DBCC).
data block See page.
data cache See buffer cache.
data control language (DCL) The subset of SQL statements used to control permissions on database objects. Permissions are controlled using the GRANT and REVOKE statements. See also data definition language (DDL); data manipulation language (DML).
data definition The process of setting up databases and creating database objects, such as tables, indexes, constraints, defaults, rules, procedures, triggers, and views.
data definition language (DDL) The subset of SQL statements used for modeling the structure (rather than the contents) of a database or a cube. The DDL gives you the ability to create, modify, and remove databases and database objects.
data-definition query A SQL-specific query that contains data definition language (DDL) statements. These are statements that allow you to create or alter objects (such as tables, indexes, views, and so on) in the database.
data dictionary A system table containing descriptions of database objects and how they are structured.
data dictionary view See system tables.
data explosion The exponential growth in size of a multidimensional structure, such as a cube, because of the storage of precalculated data.
data file A file that contains data such as tables, rows, and stored procedures. Databases can span multiple data files. See log file.
data integrity The accuracy and reliability of data. Data integrity is important in both single-user and multiuser environments. In multiuser environments, where data is shared, both the potential for and the cost of data corruption are high. In large-scale relational database management system (RDBMS) environments, data integrity is a primary concern.
data lineage A mechanism for recording information to determine the source of any piece of data, and the transformations applied to that data using Data Transformation Services (DTS). Data lineage can be tracked at the package and row levels of a table and provides a complete audit trail for information stored in a data warehouse. Data lineage is available only for packages stored in Microsoft Repository.
data manipulation language (DML) The subset of SQL statements used to retrieve and manipulate data—for example, SELECT, INSERT, UPDATE, and DELETE.
data mart A subset of the contents of a data warehouse, stored within its database. A data mart tends to contain data focused at the department level, or on a specific business area. It is frequently implemented to manage the volume and scope of data. See also data warehouse.
data migration The process of extracting data from operational systems to a data warehouse with minimal effect on the source systems, and the transformation of the source data into a format consistent with the design and requirements of the data warehouse. See also data transformation; data warehouse.
data model See relational data model.
data modification Adding, deleting, or changing information in a database by using the INSERT, DELETE, and UPDATE Transact-SQL statements.
data pump An OLE DB service provider that provides the infrastructure to import, export, and transform data between heterogeneous data stores using Data Transformation Services (DTS).
dataset In general, a collection of related information made up of separate elements that can be treated as a unit. In OLE DB for OLAP, the set of multidimensional data that is the result of executing a multidimensional expression (MDX) statement. For more information about datasets, see your OLE DB documentation.
data scrubbing The process of making data consistent, either manually, or automatically using programs. For example, a database with inconsistent data might contain customer addresses that have the State column set to "WA" for one customer but "Washington" for another. Data scrubbing is performed prior to or during the transfer of data to a data warehouse. See also data transformation.
data sharing The ability to share individual pieces of data transparently from a database across different applications.
data source The source of data for an object such as a cube or a dimension. Also, the specification of the information necessary to access source data. Sometimes refers to a DataSource object. See also data source name (DSN).
data source name (DSN) The name assigned to an ODBC data source. Applications can use data source names (DSNs) to request a connection to a system ODBC data source, which specifies the computer name and (optionally) the database to which the DSN maps. A DSN can also refer to an OLE DB connection.
data synchronization See synchronization.
data transfer The process of copying data to or from a computer running SQL Server.
data transformation A set of operations applied to source data before it can be stored in the destination, using Data Transformation Services (DTS). For example, DTS allows new values to be calculated from one or more source columns, or a single column to be broken into multiple values to be stored in separate destination columns. Data transformation is often associated with the process of copying data into a data warehouse.
Data Transformation Services (DTS) A SQL Server component used to import, export, and transform data from different data sources.
data type An attribute that specifies what type of information can be stored in a column or variable. System-supplied data types are provided by SQL Server; user-defined data types can also be created. See also base data type.
data type conversion functions Functions that transform expressions from one data type into another. The CAST and CONVERT functions provide this capability.
data warehouse A database specifically structured for query and analysis. A data warehouse typically contains data representing the business history of an organization. Data in a data warehouse is usually less detailed and longer lived than data from an OLTP system. For example, a data warehouse may store daily order totals by customer over the past 5 years, whereas an OLTP system would store every order processed but retain those records for only a few months.
date and time functions Functions used to display information about dates and times. They manipulate datetime and smalldatetime values, including arithmetic.
datetime data type A SQL Server system data type. A datetime data type is stored in 8 bytes of two 4-byte integers: 4 bytes for the number of days before or after the base date of January 1, 1900, and 4 bytes for the number of milliseconds after midnight.
DBCC See Database Consistency Checker (DBCC).
DBCS (Double-Byte Character Set) A character set that uses 1 or 2 bytes to represent a character, allowing more than 256 characters to be represented. Double Byte Character Set (DBCS) character sets are typically used in environments that use ideographic writing systems, such as Japanese, Korean, and Chinese. See also Unicode.
DB-Library A series of high-level language (including C) libraries that provide the application programming interface (API) for the client in a client/server system. DB-Library sends requests from a client to a server. DB-Library allows the developer to incorporate Transact-SQL statements into an application to retrieve and update data in a SQL Server database.
DBMS See database management system (DBMS).
DBO See database owner.
DCL See data control language (DCL).
DDL See data definition language (DDL).
deadlock A situation in which two users, each having a lock on one piece of data, attempt to acquire a lock on the other's piece. Each user waits for the other to release the lock. SQL Server detects deadlocks and terminates one user's process. See also livelock.
decision support Database applications optimized for performance in data queries that do not change data. Decision support typically requires read-only access to data.
Decision Support Objects (DSO) The Microsoft SQL Server OLAP Services server object model. Decision Support Objects (DSO) are used to create applications that define and manage cubes and other objects. DSOs can also be used to extend the functionality of the OLAP Manager or to automate the ongoing maintenance of your system.
declarative referential integrity (DRI) The SQL Server built-in capacity that checks the data integrity of a specific related table. Implemented using PRIMARY, UNIQUE and FOREIGN KEY (REFERENCES) constraints.
default A value inserted into a column automatically if the user does not enter one. In a relational database management system, every data element (a particular column in a particular row) must contain a value, even if that value is NULL. Because some columns do not accept null values, another value must be entered, either by the user or by SQL Server. In general computing terms, the behavior exhibited by a statement or a component unless overridden by the user.
default database The database the user is connected to immediately after logging on to SQL Server.
default language The language (for example, French, German, or English) used to communicate with the server. After the default language is set, the user is logged on automatically using that language.
default result set The default mode SQL Server uses to return a result set back to a client. Rows are sent to the client in the order they are placed in the result set, and the application must process the rows in this order. After executing a SQL statement on a connection, the application cannot do anything on the connection other than retrieve the rows in the result set until all of the rows have been retrieved. The only other action that an application can perform before the end of the result set is to cancel the remainder of the result set. This is the fastest method to get rows from SQL Server to the client.
delete query A query that removes rows from one or more tables.
delimiter The character used for separating elements in a list.
denormalization See denormalize.
denormalize To introduce redundancy into a table in order to incorporate data from a related table. The related table can then be eliminated. Denormalization can improve efficiency and performance by reducing complexity in a data warehouse schema. Denormalization is also sometimes used in OLTP databases to optimize certain operations. See also star schema.
density The relative percentage of a multidimensional structure's cells that contain data. OLAP Services stores only cells that contain data. A dense cube requires more storage than a sparse cube of identical structure design. See also data explosion; sparsity.
deny To remove a permission from a user account and prevent the account from gaining permission through membership in groups or roles within the permission.
dependencies The views and procedures that depend on the specified table or view.
descendant A member in a dimension hierarchy that is related to a member of a higher level within the same dimension. For example, in a Time dimension containing the levels Year, Quarter, Month, and Day, January is a descendant of 1997. See also ancestor; child; parent; sibling.
destination database See subscription database.
destination server See Subscriber.
destination table The subscribing table created as a replica of a published table. A destination table in a subscription database is synchronized with and contains data derived from the published table in a publication database.
details pane In SQL Server Enterprise Manager, which opens with Microsoft Management Console, the left-hand panel is known as the console tree. Highlighting objects in the console tree will determine which details are shown in the details pane, which is the right-hand panel. See also console tree.
device In general computing, a hardware component—for example, a hard drive or tape backup unit. In SQL Server 6.5, devices are operating system files that contain databases. In SQL Server 7, devices are not used to store databases. Backups are stored in devices. See also file.
differential database backup A database backup that records only pages that have changed in the database since the last full database backup. A differential backup is smaller and faster to restore than a full backup and has minimal effect on performance.
dimension A structural attribute of a cube, which is an organized hierarchy of categories (levels) that describe data in the fact table. These categories typically describe a similar set of members upon which the user wants to base an analysis. For example, a geography dimension might include levels for Country, Region, State or Province, and City. See also level; measure.
dimension editor A tool in the OLAP Manager that you can use to create, examine, and edit a dimension and its levels. It offers two views: Schema, which examines and edits the dimension table structure, and Browse, which checks dimension data.
dimension hierarchy One of the hierarchies of a dimension. See also hierarchy.
dimension table A table in a data warehouse whose entries describe data in a fact table. Dimension tables present business entities.
direct response mode The default mode in which SQL Server statistics are gathered separately from the SQL Server Statistics display. Data is available immediately to SQL Server Performance Monitor; however, the statistics displayed are one period behind the statistics retrieved.
dirty pages Cached pages that have been modified since the last checkpoint.
dirty read Reads that contain uncommitted data. For example, transaction 1 changes a row. Transaction 2 reads the changed row before transaction 1 commits the change. If transaction 1 rolls back the change, transaction 2 reads a row that is considered to have never existed.
disk mirroring The process that protects against media failure by maintaining a fully redundant copy of a partition on another disk. It is recommended that you use a redundant array of independent disks (RAID) for disk mirroring.
distribute To move transactions or snapshots of data from the Publisher to Subscribers, where they are applied to the destination tables in the subscription databases.
distributed database A database implemented on a network in which the component partitions are distributed over various nodes of the network. Depending on the specific update and retrieval traffic, distributing the database can enhance overall performance significantly.
Distributed Management Objects (DMO) SQL Distributed Management Objects (SQL-DMO) are 32-bit component object model (COM) objects for the Windows 95, Windows 98, and Windows NT operating systems. SQL-DMO objects are OLE Automation compatible. The SQL-DMO object model includes objects, properties, methods, and collections used to write programs to administer multiple SQL Servers distributed across a network. SQL-DMO programs can range from simple Visual Basic scripts to complex Visual C++ applications.
distributed processing Data processing in which some or all of the processing, storage, and control functions, in addition to input/output functions, are situated in different places and connected by transmission facilities. The transparent access of both applications and data by programs and users is an important goal of distributed processing systems.
distributed query A single query that accesses data from heterogeneous data sources.
Distribution Agent The replication component that moves the transactions and snapshot jobs held in distribution database tables to Subscribers.
distribution database A store-and-forward database that holds all transactions waiting to be distributed to Subscribers. The distribution database receives transactions sent to it from the Publisher by the Log Reader Agent and holds them until the Distribution Agent moves them to the Subscribers.
distribution process In replication, the process that moves transactions from the distribution database tables to subscription servers, where they are applied to the destination tables in the destination databases.
Distributor The server containing the distribution database. The Distributor receives all changes to published data, stores the changes in its distribution database, and transmits them to Subscribers. The Distributor may or may not be the same computer as the Publisher. See also local Distributor; remote Distributor.
DLL See dynamic link library (DLL).
DML See data manipulation language (DML).
DMO See Distributed Management Objects (DMO).
domain In Windows NT security, a collection of computers grouped for viewing and administrative purposes that share a common security database.
domain integrity Integrity that enforces valid entries for a given column. Domain integrity is enforced by restricting the type (through data types), the format (through CHECK constraints and rules), or the range of possible values (through REFERENCE and CHECK constraints, and rules).
DRI See declarative referential integrity (DRI).
drill down/drill up A technique for navigating through levels of data ranging from the most summarized (up) to the most detailed (down). For example, to view the details of sales data by year, a user can drill down to display sales data by quarter, and drill down further to display data by month.
DSO See Decision Support Objects (DSO).
DTS See Data Transformation Services (DTS).
dump See back up.
dump file See backup file.
dynamic backup A backup performed while the database is active.
dynamic cursor A cursor that can reflect data modifications made to the underlying data while the cursor is open. Updates, deletes, and inserts made by users are reflected in the dynamic cursor.
dynamic link library (DLL) An executable routine containing a specific set of functions stored in a .DLL file and loaded on demand when needed by the program that calls it.
dynamic locking The process used by SQL Server to determine the most cost-effective locks to use at any one time.
dynamic recovery The process that detects and/or attempts to correct software failure or loss of data integrity within a relational database management system (RDBMS).
dynamic SQL statements In Embedded SQL for C, a SQL statement built and executed at run time.
E
element The location where a row and a column meet in a table. Element is synonymous with field.
enabling The process of allowing full-text querying to occur on the current database. Execute sp_fulltext_database with action set to enable.
encrypted trigger A trigger created with an optional encryption parameter that encrypts the definition text and cannot be decrypted. Encryption makes the information indecipherable to protect it from unauthorized viewing or use.
encryption A method for keeping sensitive information confidential by changing data into an unreadable form.
entity A real-world object, referred to by a noun (person, place, thing, or idea)—for example, titles, authors, and publishers.
entity integrity Integrity that defines a row as a unique entity for a particular table and ensures that the column cannot contain duplicate values. It usually enforces the primary key of a table (through indexes, UNIQUE constraints, or PRIMARY KEY constraints).
equijoin A join in which the values in the columns being joined are compared for equality, and all columns are included in the results.
error log A log file that records information from SQL Server. You can view the error log by using SQL Server Enterprise Manager or any text editor. Each time SQL Server is started, it retains the previous logs and creates a new log.
error state number A number that provides information about the context of an error. Valid error state numbers are from 1 through 127. An error state number identifies the source of the error (if the error can be issued from more than one source).
escape character A character used to indicate that another character in an expression is meant literally and not as an operator.
event log A file that contains both SQL Server error messages and messages for all activities on the computer.
exclusive lock A lock that prevents any other transaction from acquiring a lock on a resource until the original lock on the resource is released at the end of the transaction. An exclusive lock is always applied during an update operation (INSERT, UPDATE, or DELETE).
explicit transaction A group of SQL statements enclosed in the transaction delimiters BEGIN TRANSACTION and COMMIT TRANSACTION, and optionally one of the following statements:
export file See bcp files.
expression A column name, function, variable, subquery, or any combination of column names, constants, and functions connected by an operator or operators in a subquery.
extended relational analysis A systematic database design process. The database is designed by modeling entities into tables, relationships into columns or tables, and attributes into columns.
extended stored procedure A SQL Server_provided procedure that dynamically loads and executes a function within a dynamic link library (DLL) in a manner similar to a stored procedure. Actions outside of SQL Server can be triggered and external information returned to SQL Server. Return status codes and output parameters (identical to their counterparts in regular stored procedures) are also supported.
extent The space allocated upon creation of a SQL Server object, such as a table or index. In SQL Server, an extent is eight contiguous pages.
extent lock A lock held on a group of eight database pages while they are being allocated or freed. Extent locks are set while a CREATE or DROP statement is running or while an INSERT or UPDATE statement that requires new data or index pages is running.
F
fact A row in a fact table in a data warehouse. A fact contains one or more numeric values that measure a data event such as a sales transaction.
fact table A central table in a data warehouse that contains numerical measures and keys relating facts to a dimension table. Fact tables contain data that describes a specific event within a business, such as a bank transaction or product sale. See also data warehouse; dimension table; snowflake schema; star join; star schema.
FAT file system A method for managing disk storage. A file allocation table (FAT) file system is used by an operating system to keep track of the status of various segments of disk space used for file storage. See also Windows NT File System (NTFS).
fatal error An error message with a severity level of 19 or higher. Contact your primary support provider when these errors occur.
Federal Information Processing Standard (FIPS) Standards that apply to computer systems purchased by the United States government. Each Federal Information Processing Standard (FIPS) standard is defined by the National Institute of Standards and Technology (NIST). The current standard for SQL products is FIPS 127-2, which is based on the ANSI SQL-92 standard. ANSI SQL-92 is aligned with ISO/IEC SQL-92.
fetch An operation that retrieves a row or block of rows from a cursor. Forward-only cursors support a FETCH NEXT statement only. Scrollable cursors support FETCH NEXT as well as FETCH FIRST, FETCH LAST, FETCH PRIOR, FETCH RELATIVE(n), and FETCH ABSOLUTE(n). FETCH RELATIVE(n) fetches the row n rows from the current position in the cursor. FETCH ABSOLUTE(n) fetches the nth row in the cursor. Transact-SQL batches, stored procedures, and triggers use the FETCH statement to fetch from Transact-SQL cursors. Applications use application programming interface (API) functions, such as the ODBC SQLFetch and SQLFetchScroll functions.
field A single item of information contained within a row. A field is more commonly called a column in a SQL database.
field length The maximum number of characters needed to represent data in a bulk copy character format data file.
field terminator One or many characters marking the end of a field or row, separating one field or row in the data file from the next.
file A file in which a database is stored. One database can be stored in several files. SQL Server uses three types of files: data files (which store data), log files (which store transaction logs), and backup files (which store backups of a database).
filegroup A named collection of one or more database files that forms a single unit of allocation and administration. Filegroups enable the creation of objects in a specific place—for example, placing a heavily accessed table on a very fast drive. They also provide the ability to back up specific objects.
file storage type A storage type that describes how data is stored in a bulk copy data file.
file system The portion of an operating system that translates file-operations requests from an application into low-level, sector-oriented tasks that can be understood by the drivers that control the disk drives. SQL Server is usually installed on disk drives formatted for the Windows NT file system (NTFS) or file allocation table (FAT) file systems. It can be installed on a compressed NTFS volume, but at a performance cost.
fill factor An option used when creating an index to reserve free space on each page of the index. This option accommodates future expansion of table data and reduces the potential for page splits. It is a percentage from 0 through 100 that specifies how much of the data pages should be filled after the index is created.
filter A set of criteria applied to records to show a subset of the records or to sort the records.
filtering To designate selected rows or columns of a table for replication as an article. See also horizontal filtering; partitioning; vertical filtering.
FIPS See Federal Information Processing Standard (FIPS).
firehose cursors Obsolete term for default result sets. See also default result set.
fixed database role A predefined role defined at the database level and existing in each database.
fixed server role A predefined role defined at the server level and existing outside individual databases.
FK See foreign key (FK).
float data type A data type that holds positive or negative floating-point numbers. SQL Server float data types are float, double precision, and float(n) .
foreign key (FK) The column or combination of columns whose values match the primary key (PK) or unique key in the same or another table. A foreign key does not have to be unique. A foreign key is often in a many-to-one relationship with a primary key. Foreign key values should be copies of the primary key values; no value in the foreign key except NULL should ever exist unless the same value exists in the primary key. A foreign key may be NULL; if any part of a composite foreign key is NULL, the entire foreign key must be NULL.
FOREIGN KEY constraint When a FOREIGN KEY constraint is placed on a column, any inserted data must equal the value of the referenced PRIMARY KEY or UNIQUE constraint. FOREIGN KEY constraints enforce referential integrity by preventing the deletion of parent rows that have related rows in the child table and the insertion of child rows that have no related record in the parent table. See also child; parent.
forwarding server A server running SQL Server that receives designated events.
forward-only cursor A cursor that cannot be scrolled; rows can be read only in sequence from the first row to the last row.
fragmentation A condition that occurs when data modifications are made. You can reduce fragmentation and improve read-ahead performance by dropping and re-creating a clustered index. DBCC DBREINDEX, which can rebuild all of the indexes for a table in one statement, is often used to defragment tables.
front end Software used to access a database or capture input data.
full outer join A type of outer join in which all rows in all joined tables are included, whether they are matched or not.
full-text catalog A catalog that stores a database's full-text index.
full-text index The portion of a full-text catalog that stores all of the full-text words and their locations for a given table.
full-text query As a SELECT statement, a query that searches for words, phrases, or multiple forms of a word or phrase in the character-based columns (of char, varchar, text, ntext, nchar, or nvarchar data types). The SELECT statement returns those rows meeting the search criteria.
full-text service The SQL Server component that performs the full-text querying.
function A set of instructions that operates as a single logical unit, can be called by name, accepts input parameters, and returns information. In programming languages such as C, a function is a named subroutine of a program that encapsulates some logic. The function can be called by name, using parameters to pass data into the function and retrieve data produced by the function. In Transact-SQL, a function is a unit of syntax consisting of a keyword and, usually, a set of parameters. There are several categories of Transact-SQL functions: string, math, system, niladic, text and image, date, aggregate, and conversion functions.
G
gateway A network software product that allows computers or networks running dissimilar protocols to communicate, providing transparent access to a variety of foreign database management systems (DBMSs). A gateway moves specific database connectivity and conversion processing from individual client computers to a single server computer. Communication is enabled by translating up one protocol stack and down the other. Gateways usually operate at the session layer.
gateway server A network server on which a gateway application resides.
Global Allocation Map (GAM) Pages that record what extents have been allocated. Each GAM covers 64,000 extents, or nearly 4 GB of data. The GAM has one bit for each extent in the interval it covers. If the bit is 1, the extent is free; if the bit is 0, the extent is allocated.
global group A Windows NT group containing user accounts from the Windows NT Server domain in which it is created. Global groups cannot contain other groups or users from other domains and cannot be created on a computer running Windows NT Workstation.
global variable In SQL Server 7, a variable that can be referenced by multiple Data Transformation Services (DTS) tasks. In earlier versions of SQL Server, the term referred to the Transact-SQL system functions whose names start with two at signs (@@).
grant To apply a permission to a user account, allowing the account to perform an activity or work with data.
granularity The degree of specificity of information contained in a data element. A fact table that has fine granularity contains many discrete facts, such as individual sales transactions. A table that has coarse granularity stores facts that are summaries of individual elements, such as sales totals per day.
graphical showplan An option of SQL Server Query Analyzer and SQL Server Enterprise Manager that shows the execution plan for a query. See also showplan.
group An administrative unit within Windows NT that contains Windows NT users or other groups.
guest A special user account in each database for logins without a database user account. Guests can be removed from a database.
H
hash join A sophisticated join algorithm that builds an interim structure to derive result sets. See also nested loops joins.
heterogeneous data Any non-SQL Server data. Heterogeneous data can be accessed in place through OLE DB, Linked Servers, ODBC, and the OPENROWSET and OPENQUERY commands. Heterogeneous data can be imported through Data Transformation Services (DTS), bcp, and the BULK INSERT command, among others.
hierarchy An arrangement of members of a dimension into levels based on parent-child relationships, such as Year, Quarter, Month, and Day or Country, Region, State or Province, and City. Members in a hierarchy are arranged from more general to more specific.
HOLAP (hybrid OLAP) A storage mode that uses a combination of multidimensional data structures and relational database tables to store multidimensional data. OLAP Services stores aggregations for a hybrid OLAP (HOLAP) partition in a multidimensional structure and facts in a relational database. See also MOLAP (multidimensional OLAP); ROLAP (relational OLAP).
homogeneous data Data that comes from one or more SQL Server databases.
horizontal filtering To create an article that replicates only selected rows from the base table. Subscribers receive only the subset of horizontally filtered data. You can use horizontal filtering to partition your base table horizontally. See also horizontal partitioning; vertical filtering.
horizontal partitioning To segment a single table into multiple tables based on selected rows. Each of the multiple tables has the same columns but fewer rows. See also horizontal filtering; vertical partitioning.
hybrid OLAP See HOLAP (hybrid OLAP).
I
identifier The name of a database object. An identifier can be from 1 through 128 characters. The first character must be a letter, underscore (_), at sign (@), or number sign (#). An identifier beginning with # denotes a temporary table. An identifier beginning with @ denotes a variable. Embedded spaces are not allowed.
identity column A column in a table that uses the identity property for a system-generated, monotonically increasing number.
identity property A property that enables columns to contain system-generated values that uniquely identify each row within a table. When inserting values into a table that has an identity column, SQL Server generates the next identifier automatically based on the last used identity value (incremented by adding rows) and the increment value specified during column creation.
idle time The time, in milliseconds, that SQL Server has been idle.
IEC See International Electrotechnical Commission (IEC).
image data type A SQL Server system data type of variable length that can hold from 0 through 2,147,483,647 bytes of binary data. The image data type cannot be used for variables. Conversions and calculations of hexadecimal numbers stored as binary can be unreliable.
immediate consistency A replication model that guarantees that all copies are identical to the original. It is implemented using Microsoft Distributed Transaction Coordinator (MS DTC), and it requires a high-speed, well-connected local area network (LAN). It reduces database availability and is less scalable in its implementation than latent consistency.
immediate transactional consistency A level of transaction consistency in which all participating sites are guaranteed to have the same data values at the same time, and the data is in a state that could have been achieved if all of the work had been done at one site. See also latent transactional consistency; no guaranteed consistency.
implicit transaction A transaction in which each single SQL statement is considered an atomic unit.
implied permission Permission to perform an activity specific to a role. Implied permissions cannot be granted, revoked, or denied.
incremental update The set of operations that either adds new members to an existing cube or dimension, or adds new data to a partition. One of three processing options for a cube or partition. One of two processing options for a dimension. See also process; refresh data.
index In a relational database, a database object that provides fast access to data in the rows of a table, based on key values. Indexes provide quick access to data and can enforce uniqueness on the rows in a table. SQL Server supports clustered and nonclustered indexes.
index intersection A technique that allows the query processor to evaluate multiple indexes from a table, construct a hash table from those multiple indexes, and use the hash table to reduce I/O. The resulting hash table essentially becomes a covering index and provides the same I/O performance benefits that covering indexes do.
index ORing An execution strategy that consists of looking up rows of a single table using several indexes, followed by producing the result (by combining the partial results). Usually corresponds to an OR in the WHERE <search_conditions>. For example, WHERE R.a = 6 OR R.b = 7 with indexes on columns R.a and R.b.
index page A database page containing index filters.
initial media The first medium in each media family.
initial snapshot The process that ensures that publication and destination tables contain the same schema and data before a Subscriber receives replicated transactions from a Publisher. This process is performed by the Snapshot Agent and Distribution Agent. See also synchronization.
initial synchronization See synchronization.
inner join A join in which records from two tables are combined and added to a query's results only if the values of the joined fields meet certain specified criteria, usually equality.
input member A member whose value is loaded directly from the data warehouse instead of being calculated from other data. See also calculated member.
input set The set of data provided to a multidimensional expression (MDX) value expression upon which the expression operates. For more information about set value expressions, see your OLE DB documentation.
input source Any table, view, or schema diagram used as an information source for a query.
insensitive cursor A cursor that does not reflect data modifications made to the underlying data by other users while the cursor is open. Insensitive cursors are typically used in Transact-SQL batches, stored procedures, and triggers using the INSENSITIVE keyword on the DECLARE CURSOR statement.
INSERT The Transact-SQL statement used to append new rows into a table.
Insert query A query that copies specific columns and rows from one table to another or to the same table.
installation path The drive and directory into which the SQL Server files will be copied. The default is C:\Mssql7, although this can be set at installation time. After installation, this is often referred to as the SQL Server root directory.
int (integer) data type A SQL Server system data type that holds whole numbers from 2,147,483,647 through _2,147,483,648, inclusive. You cannot enter _2,147,483,648 in an integer column, but you can enter _2,147,483,647 _ 1. You can store this number, or it can be the result of a calculation. Storage size is 4 bytes.
integrated security See Windows NT Authentication.
integrity constraint See rule.
integrity rule See constraint.
intent lock An lock that indicates that SQL Server wants to acquire a shared or exclusive lock on a more specific resource. An intent lock prevents another transaction from acquiring an exclusive lock on the resource containing that page or row.
interactive structured query language (ISQL) An interactive command-prompt utility provided with SQL Server that allows users to execute Transact-SQL statements or batches from a server or workstation and view the results returned.
International Electrotechnical Commission (IEC) One of two international standards bodies responsible for developing international data communications standards. The International Electrotechnical Commission works closely with the International Organization for Standardization (ISO) to define standards of computing. They jointly published the ISO/IEC SQL-92 standard for SQL.
International Organization for Standardization (ISO) One of two international standards bodies responsible for developing international data communications standards. The International Organization for Standardization works closely with the International Electrotechnical Commission (IEC) to define standards of computing. They jointly published the ISO/IEC SQL-92 standard for SQL.
Internet-enabled A publication setting that enables replication to Internet Subscribers.
interprocess communication (IPC) A system by which threads and processes can transfer data and messages among themselves. Interprocess communication (IPC) is used to offer and receive services from other programs.
IO busy The time, in milliseconds, that SQL Server spent performing input and output operations.
IPC See interprocess communication (IPC).
ISO See International Organization for Standardization (ISO).
isolation level An option that allows you to customize locking for an entire SQL Server session. When you set the isolation level, you specify the default locking behavior for all SELECT statements in your SQL Server session.
ISQL See interactive structured query language (ISQL).
J
job An implementation of an administrative action that contains one or more steps. The term job replaces the SQL Server 6.5 term task.
join As a verb, to combine the contents of two or more tables and produce a result set that incorporates rows and columns from each table. Tables are typically joined using data that they have in common. As a noun, join means the process or result of joining tables, as in the term inner join, which indicates a particular method of joining tables.
join condition A comparison clause that specifies how tables are related by their join fields. The most common join condition is equivalence (an equijoin) in which the values of the join fields must be the same.
join operator A comparison operator in a join condition that determines how the two sides of the condition are evaluated and which records are returned.
junction table A table that has associations with two other tables and is used indirectly as an association between those two tables. Also called a linking table. Often junction tables are used to express a many-to-many relationship, which is modeled as two one-to-many relationships.
K
kernel The essential core component of the server that handles several functions, such as task scheduling, disk caching, locking, and executing compiled queries.
key A column or group of columns that uniquely identifies a row (PRIMARY KEY), defines the relationship between two tables (FOREIGN KEY), or is used to build an index.
key column A column whose contents uniquely identify every row in a table.
key range lock A lock used to lock ranges between records in a table to prevent phantom insertions or deletions into a set of records. A key range lock also ensures serializable transactions.
keyset-driven cursor A cursor that shows the effects of updates made to its member rows by other users while the cursor is open, but does not show the effects of inserts or deletes.
keyword A reserved word in SQL Server that performs a specific function, such as to define, manipulate, and access database objects.
L
latency The amount of time that elapses between when a change is completed on the Publisher and when it appears in the destination database on the Subscriber.
latent consistency A replication model that allows a time lag between the moment that original data is altered and time that the replicated copies are updated. An advantage of latent consistency is that it supports local area networks (LANs), wide area networks (WANs), fast and slow communication links, and intermittently connected databases. SQL Server replication is based on a latent consistency model. See also immediate consistency.
latent transactional consistency A level of transaction consistency in which all participating sites are guaranteed to have the same data values that were achieved at the publishing site at some point in time. There can, however, be a delay in the data values being reflected at the participating sites, so that at any instant in time, the sites are not assured of having the exact same data values.
leaf level The bottom level of a clustered or nonclustered index. In a clustered index, the leaf level contains the actual data pages of the table. In a nonclustered index, the leaf level either points to data pages or points to the clustered index (if one exists), rather than containing the data itself.
left outer join A type of outer join in which all rows from the first-named table (the left table, which appears leftmost in the JOIN clause) are included. Unmatched rows in the right table do not appear.
level An element of a dimension hierarchy. Levels describe the dimension order from the highest (most summarized) level to the lowest (most detailed) level of data. For example, possible levels for a Geography dimension are: Country, Region, State or Province, City. See also dimension; hierarchy.
level hierarchy See dimension hierarchy; hierarchy.
library In OLAP Services, a folder that contains shared objects such as shared dimensions that can be used by multiple objects within a database.
library cache See procedure cache.
linked server An abstraction of an OLE DB data source that looks like another server to the local SQL Server. A linked server has an associated OLE DB provider that manages the data source. Linked servers allow heterogeneous data access as if the data were local SQL Server data.
linking table See junction table.
livelock A request for an exclusive lock that is repeatedly denied because a series of overlapping shared locks keep interfering. SQL Server detects the situation after four denials and refuses further shared locks. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely. See also deadlock.
load See restore.
local cube A cube created and stored with the extension .CUB on a local computer using PivotTable Service. See also PivotTable Service.
local Distributor A server configured as a Publisher that also acts as its own Distributor. In this configuration, the publication and distribution databases reside on the same computer. See also remote Distributor.
locale The set of information that corresponds to a specific language and country. A locale indicates specific settings such as decimal separators, date and time formats, and character-sorting order.
local group A Windows NT group containing user accounts and global groups from the domain group it is created in, and any trusted domain. Local groups cannot contain other local groups.
local login identification The identification (ID) that a user must use to log on to a local server. A login ID can have up to 128 characters. The characters can be alphanumeric; however, the first character must be a letter (for example, CHRIS or TELLER8).
local server The server to which the user is logged on. If remote servers are set up for the local server, users can access remote servers from their local server.
local variable A user-defined variable that has an assigned value. A local variable is defined with a DECLARE statement, assigned an initial value with a SELECT or SET statement, and used within the statement batch or procedure in which it was declared.
lock A restriction on access to a resource in a multiuser environment. SQL Server locks users out of a specific record, field, or file automatically to maintain security or prevent concurrent data manipulation problems.
lock escalation The process of converting many fine-grain locks into fewer coarse-grain locks, reducing system overhead.
log file A file or set of files containing a record of a database's transactions.
logical design An implementation-independent design that models the entities, relationships, and attributes in a database.
logical name A name used by SQL Server to identify a file. A logical name for a file must correspond to the rules for identifiers and can have as many as 128 characters.
logical operators The operators AND, OR, and NOT. These operators are used to connect search conditions in WHERE clauses.
login (account) The identity with which a user establishes a connection to SQL Server.
login identification The identification (ID) a user needs to log in to SQL Server. A login ID can have up to 128 characters and must be unique for that server. The characters can be alphanumeric; however, the first character must be a letter, the number sign (#), or underscore (_). With Windows NT Authentication, you do not need to maintain a separate login ID for SQL Server; you can use your Windows NT account.
login security mode A security mode that determines the manner in which a SQL Server validates a login request. There are two types of login security: Windows NT Authentication and Mixed Mode.
Log Reader Agent The transactional replication component that moves transactions marked for replication from the transaction log on the Publisher to the distribution database.
loose consistency A replication model that allows a time lag between the moment that original data is altered and the time that replicated copies of that data are updated. It does not guarantee that all copies will be constantly identical to the original. An advantage of loose consistency is that it supports LANs, WANs, fast and slow communication links, and intermittently connected databases. It also allows better database availability and scales much better in its implementation as compared to tight consistency. SQL Server replication is based on a loose consistency model.
lost update An update in which two transactions read and update the same data item.
M
manual synchronization Synchronization that is accomplished by a user. As with automatic synchronization, the publication server produces files containing the schema and a snapshot of the data from the published table, but with manual synchronization, it is applied to the Subscriber manually, using tape or another medium.
many-to-many relationship A relationship between two tables in which rows in each table have multiple matching rows in the related table. Many-to-many relationships are maintained by using a third table called a junction table.
MAPI Messaging Application Programming Interface. An e-mail application programming interface (API). Both SQL Mail and SQLAgentMail use MAPI.
mapped drive letter A shared resource that can be referred to as if it were a local drive. Local drives are assigned a letter of the alphabet. For example, the server share \\Server1\Quarterly Sales\ could be mapped to drive Q:. In that case a file on that shared resource could be referred to as either \\Server1\Quarterly Sales\Q1-1998.xls or Q:\Q1-1998.xls.
master database The database that controls user databases and the operation of SQL Server as a whole. It is installed automatically with SQL Server and keeps track of user accounts, remote user accounts, and remote servers that this server can interact with. It also tracks ongoing processes, configurable environment variables, system error messages, databases on SQL Server, storage space allocated to each database, tapes and disks available on the system, and active locks.
master definition site See Publisher.
master device The file installed with earlier versions of SQL Server used to store the master, model, and tempdb system databases and transaction logs and the pubs sample database and transaction log. These databases now reside on their own individual files. See also master file.
master file The database file that contains the master database.
master site See Distributor.
MDX See multidimensional expressions (MDX).
measure A quantitative, numerical column in a fact table. Measures typically represent the values that are analyzed. See also dimension.
media description The descriptive text describing the media set.
media family All media in a set written by a single device. For example, an initial medium and all continuation media, if any.
media header Information about the backup media.
media name The descriptive name for the entire backup media set.
media password The password for the entire media set. SQL Server does not support media passwords.
media retention A setting that protects backups from being overwritten until the specified number of days has elapsed.
media set All media involved in a backup operation.
member An item in a dimension representing one or more occurrences of data. A member can be either unique or nonunique. For example, 1997 and 1998 represent unique members in the year level of a Time dimension, whereas January represents nonunique members in the month level because there can be more than one January in the Time dimension if it contains data for more than one year.
MemberKeyColumn The property that specifies the identifiers for dimension members. The MemberKeyColumn specifies a column in a table or an expression that, when evaluated, results in a set of member identifiers. For example, a MonthNumber column in a Time dimension table would contain numbers from 1 through 12, corresponding to the months of the year. See also MemberNameColumn; member variable.
MemberNameColumn The property that associates names with identifiers for dimension members specified by the MemberKeyColumn property. For example, a MonthName column in a Time dimension table would contain the names Jan, Feb, Mar, and so on, to correspond to the numbers from 1 through 12 in the MonthNumber column in the same table. These names are returned to the client when queries are evaluated and can be used to make the presented data more readable. See also MemberKeyColumn; member variable.
member property Information about the members of a dimension level in addition to that contained in the dimension (for example, the color of a product or the telephone number of a sales representative). For more information about member properties, see your OLE DB documentation.
member variable The value used internally by OLAP Services to identify a dimension member. MemberKeyColumn specifies the member variables for a dimension. For example, a number from 1 through 12 could be the member variable that corresponds to a month of the year. See also MemberKeyColumn; MemberNameColumn.
memo A type of column containing long strings of text (typically more than 255 characters). This is the Microsoft Access equivalent of a SQL Server text datatype.
merge In SQL Server OLAP Services, the operation that combines two partitions into a single partition.
Merge Agent In merge replication, the component that applies initial snapshot jobs held in publication database tables to Subscribers. It also merges incremental data changes that have occurred since the initial snapshot was created.
merge replication A type of replication that allows sites to make autonomous changes to replicated data and, at a later time, merge changes made at all sites. Merge replication does not guarantee transactional consistency. See also snapshot replication; transactional replication.
message number A number that uniquely identifies an error message.
metadata Data about data. That is, information about the properties of data, such as the type of data in a column (numeric, text, and so on) or the length of a column, information about the structure of data, or information that specifies the design of objects such as cubes or dimensions. Metadata is an important aspect of SQL Server, Data Transformation Services, and OLAP Services.
method A function that performs an action by using a component object model (COM) object, as in SQL-DMO, OLE DB, and ADO.
Microsoft ActiveX Data Objects (ADO) An easy-to-use, application programming interface (API) wrapping OLE DB for use in languages such as Visual Basic, Visual Basic for Applications, Active Server Pages, and Microsoft Internet Explorer Visual Basic Scripting.
Microsoft ActiveX Data Objects (Multidimensional) (ADO MD) A high-level, language-independent set of object-based data access interfaces optimized for multidimensional data applications. Visual Basic and other automation languages use ActiveX Data Objects (Multidimensional) (ADO MD) as the data access interface to multidimensional data storage. ADO MD is a part of ADO 2.0 and later.
Microsoft Management Console (MMC) An extensible, common console framework for management applications. Both SQL Server and OLAP Services use MMC to host their administrative user interfaces, the SQL Server Enterprise Manager and OLAP Manager.
Microsoft ODBC See Open Database Connectivity (ODBC).
Microsoft Open Database Connectivity (ODBC) See Open Database Connectivity (ODBC).
Microsoft Open Data Services See Open Data Services (ODS).
Microsoft Repository A set of Microsoft ActiveX interfaces and information models that are used to define database schema and data transformations as specified by the Microsoft Data Warehousing Framework. DTS supports Repository information stored in the SQL Server msdb database. Repository is the preferred means of storing DTS packages in a data-warehousing scenario because it is the only method of providing data lineage for packages.
mirroring In general NT computing, the continuous duplication of the information on one volume to another. Either the hardware or the Windows NT operating system can provide mirroring capabilities. Mirroring can provide continuous recovery in the event of media failure.
Mixed Mode A login security mode that combines Windows NT Authentication and SQL Server Authentication. It allows users to connect to SQL Server through either a Windows NT user account or a SQL Server login.
mixed security See Mixed Mode.
MMC See Microsoft Management Console (MMC).
MOLAP (multidimensional OLAP) A storage mode that uses a proprietary multidimensional structure to store a partition's facts and aggregations. A partition's data is completely contained within the multidimensional structure. See also HOLAP (hybrid OLAP); ROLAP (relational OLAP).
model database A database installed with SQL Server that provides the template for new user databases. Each time a database is created, SQL Server makes a copy of the model and then extends it to the size requested. A new database cannot be smaller than the model. The model database contains the system tables required for each user database. You can modify the model to add objects that you want in all newly created databases.
modulo An arithmetic operator that provides the integer remainder after a division involving two integers.
money data type A SQL Server system data type that stores monetary values from +922,337,203,685,477.5807 through _922,337,203,685,477.5808 with accuracy to a ten-thousandth of a monetary unit. The storage size is 8 bytes.
multidimensional expressions (MDX) A syntax used for querying multidimensional data. For more information about multidimensional expressions (MDX), see your OLE DB documentation.
multidimensional OLAP See MOLAP (multidimensional OLAP).
multidimensional structure A database paradigm that treats data not as relational tables and columns, but as information cubes that contain dimension and summary data in cells, each addressed by a set of coordinates that specifies a position in the structure's dimensions. For example, the cell at coordinates {SALES, 1997, WASHINGTON, SOFTWARE} would contain the summary of software sales in Washington in 1997. See also cube.
multithreaded server application An application that creates multiple threads within a single process to service multiple user requests at the same time.
multiuser The ability of a computer to support many users operating at the same time, while providing the computer system's full range of capabilities to each user.
N
named pipe An interprocess communication (IPC) mechanism that SQL Server and Open Data Services use to provide communication between clients and servers. Named pipes permit access to shared network resources.
native format Data stored in a bulk copy data file using SQL Server native data types.
nchar data type A fixed-length data type with a maximum of 4000 Unicode characters. Unicode characters use 2 bytes per character and support all international characters.
nested loops joins The nested loops join, also called nested iteration, uses one join input as the outer input table (shown as the top input in the graphical execution plan) and one as the inner (bottom) input table. The outer loop consumes the outer input table row by row. The inner loop, executed for each outer row, searches for matching rows in the inner input table.
nested query A SELECT statement that contains one or more subqueries.
Net-Library SQL Server uses dynamic link libraries to communicate via a particular network protocol. The same pair of Net-Libraries must be active on both client and server computers to support the desired network protocol.
network adapter An expansion card or other physical device used to connect a computer to a local area network (LAN); also known as NIC (network interface card).
niladic functions Niladic functions allow a system-supplied value to be inserted into a table when no value is specified. ANSI-standard niladic functions are used in DEFAULT constraints.
no guaranteed consistency A level of transaction consistency in which all participating sites can have the same data values, but not necessarily the same data values that could have been achieved if all the work had been done at one site. The act of replicating the data creates the possibility that variations in data values result at one or more sites. See also immediate transactional consistency; latent transactional consistency.
no initial snapshot A replication option used when a server subscribes to a publication. This option allows changes to replicated data to be distributed immediately to Subscribers, without delay for synchronization. An initial snapshot is not performed by SQL Server; it is the responsibility of the user setting up replication to ensure that the table schema and data are identical for the published article and the destination table. See also automatic synchronization.
noise word Words that do not participate in a full-text query search. For example, a, and, the, and so on.
nonclustered index An index in which the logical order of the index does not match the physical, stored order of the rows on disk. The leaf nodes of a nonclustered index contain index rows. Each index row contains the nonclustered key value and one or more row locators that point to the data row (or rows if the index is not unique) having the key value.
nonrepeatable read When a transaction reads the same row more than one time, and between the two (or more) reads, a separate transaction modifies that row. Because the row was modified between reads within the same transaction, each read produces different values, which introduces inconsistency.
normalization rules Rules that identify certain attributes that must be present (or absent) in a well-designed database, according to commonly accepted relational theory.
Northwind database A sample database provided with SQL Server. If Northwind was not installed with SQL Server, you can install it using the Instnwnd.sql script.
ntext data type A variable-length data type that can hold a maximum of 230 _1 (1,073,741,823) characters or 231 _1 bytes, which is 2,147,483,647. ntext columns store a 16-byte pointer in the data row, and the data is stored separately.
NTFS See Windows NT File System (NTFS).
NULL An entry that has no explicitly assigned value. NULL is not equivalent to zero or blank. A value of NULL is not considered to be greater than, less than, or equivalent to any other value, including another value of NULL.
nullability The capability that determines whether a column can allow null values for the data in that column.
nvarchar data type A variable-length data type with a maximum of 4000 Unicode characters. Unicode characters use 2 bytes per character and support all international characters.
O
object One of the components of a database: a table, index, trigger, view, key, constraint, default, rule, user-defined data type, or stored procedure. Also called a database object. In COM programming, an object has properties and methods and exposes interfaces; for example, the SQL-DMO is a hierarchy of COM objects.
object dependencies The views and procedures that depend on a table or view, and the tables or views that depend on a view or procedure.
Object Linking and Embedding (OLE) An application programming interface (API) for sharing objects among applications. OLE is built on the component object model (COM).
object owner The security account with special permissions for an object, usually the creator of the object. Also called the database object owner.
object permission Permission based on a table or view; controls the ability to execute the SELECT, INSERT, UPDATE, and DELETE statements against the table or view.
ODBC See Open Database Connectivity (ODBC).
ODBC driver A dynamic link library (DLL) that an ODBC-enabled application, such as Microsoft Excel, can use to access an ODBC data source. Each ODBC driver is specific to a database management system (DBMS), such as SQL Server, Access, and so on.
ODS See Open Data Services (ODS).
ODS Library A set of C functions that makes an application a server. ODS Library calls respond to requests from a client in a client/server network. The library also manages the communication and data between the client and the server. ODS Library follows the tabular data stream (TDS) protocol.
ODS log file A text file used to store Open Data Services (ODS) error messages. The default log file for ODS is Srv.log.
OLAP See online analytical processing (OLAP).
OLAP client See client application.
OLAP Manager A Microsoft Management Console (MMC) snap-in that provides a user interface for managing the OLAP server and for designing and creating multidimensional databases, cubes, and dimensions. See also Microsoft Management Console (MMC); snap-in.
OLAP server The server component of OLAP Services that is specifically designed to create and maintain multidimensional data structures and provide multidimensional data in response to client queries. See also PivotTable Service.
OLE See Object Linking and Embedding (OLE).
OLE Automation controller A programming environment (for example, Visual Basic) that can drive Automation objects.
OLE Automation objects A component object model (COM) object that provides Automation-compatible interfaces.
OLE Automation server An OLE custom component that provides programmable Automation objects.
OLE DB A COM-based application programming interface (API) for accessing data. OLE DB supports accessing any format of data storage (databases, spreadsheets, text files, and so on) for which an OLE DB provider is available.
OLE DB consumer The application software that calls and uses the OLE DB application programming interface (API).
OLE DB for OLAP A section of OLE DB 2.0 and later that addresses multidimensional structures and OLAP. See also Microsoft ActiveX Data Objects (Multidimensional) (ADO MD); OLE DB.
OLE DB provider A software component that exposes an OLE DB interface. Each OLE DB provider is specific to a particular storage mechanism (for example, SQL Server databases, Access databases, or Excel spreadsheets).
OLTP See online transaction processing (OLTP).
one-to-many relationship A relationship between two tables in which a single row in the first table can be related to one or more rows in the second table, but a row in the second table can be related only to one row in the first table. A typical one-to-many relationship is between the publishers table and the titles table in the pubs sample database, in which each publisher can be related to several titles, but each title can be related to only one publisher.
one-to-one relationship A relationship between two tables in which a single row in the first table can be related only to one row in the second table, and a row in the second table can be related to only one row in the first table. This type of relationship is unusual.
online analytical processing (OLAP) A technology that uses multidimensional structures to provide rapid access to data for analysis. The source data for OLAP is commonly stored in data warehouses in a relational database. See also HOLAP (hybrid OLAP); MOLAP (multidimensional OLAP); ROLAP (relational OLAP).
online redo log See transaction log.
online transaction processing (OLTP) A database management system representing the state of a particular business function at a specific point in time. An OLTP database is typically characterized by having large numbers of concurrent users actively adding and modifying data.
Open Data Services (ODS) An application programming interface (API) for the server portion of a client/server system that makes data sources or data services appear to a client as a SQL Server. ODS provides a network interface that handles network protocol processes and a set of server routines that provides the application programming interface.
Open Database Connectivity (ODBC) A database-material application programming interface (API) aligned with the American National Standards Institute (ANSI) and International Organization for Standardization (ISO) standards for a database call-level interface (CLI). ODBC supports access to any database for which an ODBC driver is available.
operator A symbol used to perform mathematical computations and/or comparisons between columns or variables. In SQL Server management, an operator is a person designated to receive e-mail or pager notification of alerts and job disposition.
optimistic locking A method of locking in which data is locked when updated rather than when accessed. Optimistic locking supports higher levels of concurrency than pessimistic locking, in which data is locked when accessed.
optimizer See query optimizer.
ordered set A set of members returned in some specific order. The ORDER function in a multidimensional expression (MDX) query returns an ordered set. For more information about the ORDER function, see your OLE DB documentation.
outer join A join that includes all rows from the joined tables regardless of whether there is a matching row between the joined tables.
ownership chain When objects have dependencies, their ownership is referred to as an ownership chain. If dependent objects do not have the same owner, it is known as a broken ownership chain. Broken ownership chains complicate permissions, since all owners must grant permissions to all users of the dependent object.
P
package A Data Transformation Services (DTS) object that defines one or more tasks to be executed in a coordinated sequence to import, export, or transform data.
packet errors The number of network errors that SQL Server detects while reading and writing packets of data over the network.
packets received The number of input packets that SQL Server has read.
packets sent The number of output packets that SQL Server has written.
page In a virtual storage system, a fixed-length block of contiguous virtual addresses copied as a unit from memory to disk and back during paging operations. SQL Server allocates database space in pages. In SQL Server, a page is 8 KB in size.
page lock A lock on 8 KB of RAM (one page) that is allocated as a single unit.
page split The process of moving half the rows in a full page to a new page to make room for a new entry.
parallel query execution Execution of a single query across multiple processors.
parameter A placeholder in a query or stored procedure that can be filled in when the query or stored procedure is executed. Parameters allow you to use the same query or stored procedure many times, each time with different values. Parameters can be used for any literal value, and in some databases for column references as well.
parent A member of the next higher level in a hierarchy that is directly related to the current member. The parent value is usually a consolidation of the values of all of its children. For example, in a Time dimension containing the levels Quarter, Month, and Day, Qtr1 is the parent of January. In referential integrity, the term parent is sometime used to describe the "one" table in a parent/child, or one-to-many, relationship. See also ancestor; child; descendant; sibling.
partition In general computing terms, a formatted volume of a hard disk drive. In OLAP services, one of the storage containers for data and aggregations of a cube. Every cube contains one or more partitions. For a cube with multiple partitions, each partition can be stored separately in a different physical location. Each partition can be based on a different data source. Partitions are not visible to users; the cube appears to be a single object.
partitioning To divide a table into logical subsets based on characteristics of the data. Partitioning is used to improve application performance or reduce the potential for conflicts in multisite update replication. See also filtering; horizontal partitioning; vertical partitioning.
pass-through query A query that is passed uninterpreted to an external server for evaluation. The result set returned by a pass-through query can be used in the FROM clause of a query like an ordinary base table.
pass-through statement A SELECT statement that is passed directly to the source database without modification or delay. In PivotTable Service, the PASSTHROUGH option is part of the INSERT INTO statement. See also PivotTable Service.
Performance Monitor See Windows NT Performance Monitor.
permissions Authorization that enforces database security. SQL Server permissions specify the Transact-SQL statements, views, and stored procedures each user is authorized to use. The ability to assign permissions is determined by each user's status. There are two types of permissions: object permissions and statement permissions.
permissions validation The process of validating the activities that the user is allowed to perform in the SQL Server database.
persistence Permanent, or persistent, storage of objects and data structures that involves converting complex data structures into a format suitable for file storage.
phantom A phenomenon that occurs when a transaction attempts to select a row that does not exist and a second transaction inserts the row before the first transaction finishes. If the row is inserted, the row appears as a phantom to the first transaction, inconsistently appearing and disappearing.
physical name The path where a backup file or database file is located.
physical reads Reads and writes of the data performed by the database page.
pivot To rotate rows to columns, and columns to rows, in a crosstabular data browser. Also refers to choosing dimensions from the set of available dimensions in a multidimensional data structure for display in the rows and columns of a crosstabular structure.
PivotTable Service An in-process desktop OLAP server that communicates with the OLAP server and provides interfaces for use by client applications accessing OLAP data on the server. PivotTable Service is an OLE DB for OLAP provider. It provides online and offline data analysis functionality.
polling interval The option that sets how often the state of the service (SQL Server or SQL Server Agent) is checked.
populate See process.
position The current location of processing in a cursor. For example, after an application fetches the first 10 rows from a cursor, it is positioned on the tenth row of the cursor. Database application programming interfaces (APIs) also have functions, such as the ODBC SQLSetPos function, that allow an application to move directly to a specific position in a cursor without performing a fetch.
positioned update An update, insert, or delete performed on a row at the current position of the cursor. The actual change is made in the rows of the base tables used to build the current row in the cursor. Transact-SQL batches, stored procedures, and triggers use the WHERE CURRENT OF clause to perform positioned updates. Applications use application programming interface (API) functions, such as the ODBC SQLSetPos function, to perform positioned updates.
precalculate To compute combinations of data while a cube is being processed. Data is precalculated in anticipation of ad hoc queries to minimize computation and disk access time when a query is submitted. For example, total quantity sold for a year can be precalculated from individual sales transactions during cube processing. See also aggregation.
precision The maximum total number of decimal digits that can be stored, both to the left and right of the decimal point.
predicate An expression that returns a value of TRUE, FALSE, or UNKNOWN. Predicates are used in the search condition of WHERE and HAVING clauses of Transact-SQL statements such as SELECT and UPDATE, and in the conditions of program logic statements such as IF and WHILE.
prefix characters Characters that precede each noncharacter field in a bcp native format data file, indicating the length of the field.
prefix length The number of prefix characters preceding each field in a bcp native format data file.
prefix search Full-text query searching for those columns where the specified character-based text, word, or phrase is the prefix. When using a phrase, each word within the phrase is considered to be a prefix. For example, a prefix search specifying the phrase "sport fish" matches "sport fishing," "sportsman fishing supplies," and so on.
primary dimension table A dimension table in a snowflake schema in a data warehouse that is directly related to the fact table. Additional tables that complete the dimension definition are joined to the primary dimension table instead of to the fact table. See also dimension table; snowflake schema.
primary domain controller (PDC) A server in a Windows NT domain that maintains the domain's security database and authenticates user login passwords. It also provides a copy of the domain's security database to backup domain controllers (BDCs), which share the user login authentication load.
primary key (PK) The column or combination of columns that uniquely identifies one row from any other row in a table. A primary key (PK) must be nonnull and must have a unique index. A primary key is commonly used for joins with foreign keys (matching nonprimary keys) in other tables.
private data space A structure passed to Open Data Services event handlers that contains information to make and use a connection to a remote database management system.
private dimension A dimension created for and used by a specific cube. Unlike shared dimensions, private dimensions are available only to the cube in which they are created. See also shared dimension.
procedure A collection of stored Transact-SQL statements that can be called from one or more locations in program code.
procedure cache A temporary storage location for the current, executing version of a specific stored procedure.
process In a cube, the series of operations that rebuilds the cube's structure, loads data into a multidimensional structure, calculates summaries, and saves the precalculated aggregations. As a verb, to populate a cube with data and aggregations; one of three processing options for a cube. In a dimension, the operation that loads data from a dimension table in a data warehouse into the levels defined for a dimension and rebuilds the structure of the dimension; one of two processing options for a dimension. See also incremental update; refresh data.
producer Any process that collects events in a specific event category and sends the data to a SQL Server Profiler queue.
projection The process of extracting data from fewer than all available columns in a table or set of tables.
protocol A set of rules or standards designed to enable computers to connect with one another and exchange information.
provider An OLE DB provider. A provider is an in-process dynamic link library (DLL) that provides access to a database.
proximity search Full-text query searching for those columns in which the specified words are close to one another.
publication A group of articles available for replication as a unit. A publication can contain one or more published tables or stored procedure articles from one user database. Each user database can have one or more publications.
Publication Access List A list of logins that have access to a publication. The default Publication Access List on a server controls access to all publications on that server not having a custom Publication Access List.
publication database A database source of replicated data that contains tables for replication.
publish To make data available for replication.
Publisher A server that makes data available for replication. A Publisher maintains publication databases and sends copies of all changes of the published data to the Distributor.
pubs database A sample database provided with SQL Server. If pubs was not installed with SQL Server, you can install it using the Instpubs.sql script.
pull subscription A type of subscription in which the initiation of data movement is made at the Subscriber. The Subscriber maintains a subscription by requesting, or pulling, data changes from a Publisher. The Distribution Agent is maintained at the Subscriber, thereby reducing the amount of overhead at the Distributor. See also push subscription.
push subscription A subscription in which the initiation of data movement is made at the Publisher. The Publisher maintains a subscription by sending, or pushing, the appropriate data changes to one or more Subscribers. The Distribution Agent is maintained at the Distributor. See also pull subscription.
Q
query A specific request for data retrieval, modification, or deletion.
query optimizer The SQL Server component responsible for generating the optimum execution plan for a query.
queue In SQL Server Profiler, a temporary holding place for server events to be captured.
R
RAID (redundant array of independent disks) Sometimes referred to as redundant array of inexpensive disks, a system that uses multiple disk drives (an array) to provide performance and reliability. There are six levels describing RAID arrays, 0 through 5. Each level uses a different algorithm to implement fault tolerance.
range query A query that specifies a range of values as part of the search criteria, such as all rows from within a column valued from 10 through 100.
ranking A value indicating the degree of matching (0 is a very low degree of matching and 1000 is the highest degree of matching) of each value that is determined to match a full-text query.
RDBMS See relational database management system (RDBMS).
read-only replica A publication that cannot be updated or changed by the Subscriber.
read-only snapshot See read-only replica.
real data type A SQL Server system data type that has 7-digit precision. The approximate range of values is from 3.4E _ 38 through 3.4E + 38. Storage size is 4 bytes.
record A group of related fields (columns) of information treated as a unit. A record is more commonly called a row in a SQL database.
recordset The ADO object used to contain a result set. It also exhibits cursor behavior depending on the recordset properties set by an application. ADO recordsets are mapped to OLE DB rowsets.
recovery See automatic recovery.
recovery interval The interval that determines checkpoint frequency by specifying the amount of time it should take the system to recover.
redo log file See backup file.
referential integrity (RI) An integrity mechanism that ensures that vital data in a database, such as the unique identifier for a given piece of data, remains accurate and usable as the database changes. Referential integrity involves managing corresponding data values between tables when the foreign key of a table contains the same values as the primary key of another table.
reflexive relationship A relationship from a column or combination of columns in a table to other columns in that same table. A reflexive relationship is used to compare rows within the same table. In queries, this is called a self-join.
refresh data The series of operations that clears data from a cube, loads the cube with new data from the data warehouse, and calculates aggregations. Refresh data is used when a cube's underlying data in the data warehouse changes but the cube's structure and aggregation definitions remain the same. One of three processing options for a cube. See also incremental update; process.
registry A database repository that contains information about a computer's configuration. It is organized hierarchically and comprises subtrees and their keys, hives, and value entries.
relational data model A method of organizing data into two-dimensional tables made up of rows and columns. The model is based on the mathematical theory of relations, a part of set theory.
relational database A collection of information organized in tables, each of which models a class of objects of interest to the organization (for example, Customers, Parts, Suppliers). Each column in a table models an attribute of the object modeled by the table (for example, LastName, Price, Color). Each row in a table represents one entity in the class of objects modeled by the table (for example, the customer named John Smith or the part numbered 1346). Queries can use data from one table to find related data in other tables.
relational database management system (RDBMS) A system that organizes data into related rows and columns. SQL Server is a relational database management system.
relational OLAP See ROLAP (relational OLAP).
relationship A link between tables that references the primary key in one table to a foreign key in another table. The relationship line is represented in a database diagram by a solid line if referential integrity between the tables is enforced, or a dashed line if referential integrity is not enforced for INSERT and UPDATE transactions. The endpoints of a relationship line show a primary key symbol to denote a primary-key-to-foreign-key relationship or an infinity symbol to denote the foreign key side of a one-to-many relationship.
remote data Data stored on a computer other than the computer running SQL Server and accessed by either establishing a linked server or using the ad hoc connector name.
remote Distributor A server configured as a Distributor but on a separate computer from the Publisher. In this configuration, the publication and distribution databases reside on separate computers. See also local Distributor.
remote login identification The login identification (login ID) assigned to a user for accessing remote procedures on a remote server. This login ID can be the same as the user's local login ID. A remote login ID can have up to 128 characters. The characters can be alphanumeric; however, the first character must be a letter (for example, CHRIS or TELLER8).
remote procedure call (RPC) In general networking terms, a call that uses IPC mechanisms such as named pipes to establish communications between the client and the server. In SQL Server terms, the invocation of a stored procedure on a remote server from a procedure on a server.
remote server A SQL Server on the network that can be accessed through a user's local server. SQL Server Setup can install, upgrade, or configure remote servers.
remote stored procedure A collection of SQL statements and optional control-of-flow statements stored under a name on a remote server. Remote stored procedures can be called by clients or by SQL Server.
remote stored procedure event An Open Data Services event that occurs when a client or server calls a remote stored procedure.
remote table A table external to the local SQL Server data source.
replica A copy of objects in a publication received when a server subscribes to the publication.
replication Duplication of table schema and data or stored procedure definitions and calls from a source database to a destination database, usually on separate servers.
Replication Monitor A graphical tool in SQL Server Enterprise Manager used to simplify replication monitoring and troubleshooting.
report generator A software component that produces formatted output from a database.
repository The storage container for the metadata managed by OLAP Services. Metadata is stored in tables in a relational database and is used to define the parameters and properties of OLAP server objects. See also metadata; Microsoft Repository.
restore To restore an entire database and transaction log, database file(s), or a transaction log from a backup.
restricted publication In replication, a security status. A publication marked Restricted cannot be subscribed to by any registered Subscriber. See also unrestricted publication.
results completion message A message sent to a client with srv_senddone indicating that one set of results has been sent to the client.
result set The set of rows returned from a SELECT statement. The format of the rows in the result set is defined by the column-list of the SELECT statement.
retention In replication, the period of time for which a transaction is maintained in the distribution database. In backup media, a specified time period during which backups cannot be overwritten.
return parameters Output parameters returned by an ODS Library function to the client.
reusable bookmark A bookmark that can be consumed from a rowset for a given table and used on a different rowset of the same table to position on a corresponding row.
revoke To remove a previously granted or denied permission from a user account in the current database. The user account may then acquire the permission through membership in groups or roles.
RI See referential integrity (RI).
right outer join A type of outer join in which all rows in the second-named table (the right table, the one that appears rightmost in the JOIN clause) are included. Unmatched rows in the left table are not included.
ROLAP (relational OLAP) A storage mode that uses tables in a relational database to store multidimensional structures. See also HOLAP (hybrid OLAP); MOLAP (multidimensional OLAP).
role An administrative unit within SQL Server that contains SQL Server logins, Windows NT logins, groups, or other roles. See also group; SQL Server role.
roll back To remove partially completed transactions after a database or other system failure. See also commit; roll forward.
roll forward To recover from disasters, such as media failure, by reading the transaction log and reapplying all readable and complete transactions. See also roll back.
root directory See installation path.
rotate See pivot.
row A data structure that is a collection of elements (columns), each with its own name and type. A row can be accessed as a collective unit of elements, or the elements can be accessed individually. A row is equivalent to a record. See also column.
row aggregate A function (SUM, AVG, MAX, MIN, or COUNT) used on a group or aggregate of data.
row aggregate function A function that generates summary values that appear as additional rows in the query results (unlike aggregate function results that appear as new columns). A row aggregate function allows you to see detail and summary rows in one set of results. Row aggregate functions (SUM, AVG, MIN, MAX, and COUNT) are used in a SELECT statement with the COMPUTE clause.
row-level locking See row lock.
row lock A lock on a single row in a table.
rowset The OLE DB object used to contain a result set. It also exhibits cursor behavior depending on the rowset properties set by an application.
rule A database object that is bound to a column or user-defined data type that specifies what data can be entered in that column. Every time a user enters or modifies a value (with an INSERT or UPDATE statement), SQL Server checks it against the most recent rule bound to the specified column—for example, for limit checking or list checking. Data entered before the creation and binding of a rule is not checked. Rules are supported primarily for backward compatibility.
S
sa See system administrator.
sample data Artificially generated data presented instead of actual data when a cube is queried before it has been processed. Sample data enables you to view the effects of structural changes while modifying a cube.
savepoint A marker that the user includes in a user-defined transaction. When transactions are rolled back, they can be rolled back only to the savepoint.
scalability A characteristic of a system that provides increased performance with the addition of resources. SQL Server is scalable. For example, it can use memory or additional processors to accommodate more user connections.
scalar aggregate A function applied to all of the rows in a table (producing a single value per function). An aggregate function in the select list with no GROUP BY clause applies to the whole table and is an example of a scalar.
scalar function A function that operates on a single value and then returns a single value. Scalar functions can be used wherever an expression is valid.
scalar subquery A SELECT statement that evaluates to a single value for each result set row. Scalar subqueries can be used in place of expressions if they return a single value.
scheduled backup An automatic backup accomplished by SQL Server Agent when defined and scheduled as a job.
scheduled table refresh See snapshot replication.
schema A description of a database generated by the data definition language (DDL) of the database management system (DBMS). In OLAP Services, a schema is a description of multidimensional objects such as cubes, dimensions, and so forth.
schema script See table schema script.
script A collection of Transact-SQL statements used to perform an operation. Transact-SQL scripts are stored as files, usually with the .SQL extension.
scroll The ability to move around with a cursor in directions other than forward-only. Users can move up and down with the cursor.
search condition In a WHERE or HAVING clause, conditions to be met for the specified action to occur on the specified data.
Security Identifier (SID) A unique value that identifies a user who is logged on to the security system. Security IDs (SIDs) can identify either one user or a group of users.
Security Principal An entity (for example, a user, group, or computer) that has been assigned an ID for security purposes.
segment In SQL 7, segments are replaced by filegroups. See also filegroup.
SELECT The Transact-SQL statement used to request a selection, projection, join, query, and so on from a SQL Server database.
select list The information (columns, expressions, and so on) to return from the specified tables in a query.
Select query A query that returns rows into a result set from one or more tables. A Select query can contain specifications for those columns to return, the rows to select, the order to put the rows in, and how to group (summarize) information.
selection An extraction of data from a subset of all rows of a table or set of tables.
self-join A join that compares rows within the same table. In database diagrams, a self-join is called a reflexive relationship.
sensitive cursor A cursor that can reflect data modifications made to underlying data by other users while the cursor is open. Updates, deletes, and inserts made by other users are reflected in the sensitive cursor. Sensitive cursors are typically used in Transact-SQL batches, stored procedures, and triggers by omitting the INSENSITIVE keyword on the DECLARE CURSOR statement.
sequence See identity column.
sequential file A file whose records are arranged in the order in which they are placed in the file.
serializable A transaction isolation level that ensures a database changes from one predictable state to another. If multiple concurrent transactions can be executed serially, and the results are the same, the transactions are considered serializable.
server A computer on a local area network (LAN) that controls access to resources, such as files, printers, and communication devices. See also OLAP server.
server cursor A cursor that is implemented on the server. The cursor itself is built at the server, and only the rows fetched by an application are sent to the client.
server name The name a client uses to identify a server running SQL Server. The server names on a client are managed by using the Client Network Utility. It is also the name used by one SQL Server when making a remote stored procedure call to another SQL Server.
server process ID A unique integer assigned to every server process, including user connections.
server state polling The polling interval, used to set how often the state of the service is checked.
service A process that performs a specific system function and often provides an application programming interface (API) for other processes to call. It runs independently on a computer running Windows NT, unlike a program that requires a logged-on user to start or stop the program.
session-level setting A setting that applies to the current connection. Settings can apply to the entire server, the database, or the individual user connection.
setup initialization file A text file, using the Windows .INI file format, that stores configuration information allowing SQL Server to be installed without a user having to be present to respond to prompts from the Setup program.
severity level number The severity level of an error. Valid levels are from 1 through 25. Only the system administrator can add a message with a severity level from 19 through 25.
shared dimension A dimension created within a database that can be used by any cube in the database. See also private dimension.
Shared Global Allocation Map (SGAM) Pages that record what extents are currently used as mixed extents and have at least one unused page. Each SGAM covers 64,000 extents, or nearly 4 GB of data. The SGAM has one bit for each extent in the interval it covers. If the bit is 1, the extent is being used as a mixed extent and has free pages; if the bit is 0, the extent is not being used as a mixed extent, or it is a mixed extent whose pages are all in use.
shared lock A lock created by nonupdate (read) operations. Other users can read the data concurrently, but no transaction can acquire an exclusive lock on the data until all of the shared locks have been released.
showplan A report showing the execution plan for a SQL statement. SET SHOWPLAN_TEXT and SET SHOWPLAN_ALL produce textual showplan output. SQL Server Query Analyzer and SQL Server Enterprise Manager can display showplan information as a graphical tree.
sibling A member in a dimension hierarchy that is a child of the same parent as a specified member. For example, in a Time dimension with Year and Month levels, the members January 1997 and February 1997 are siblings. See also ancestor; child; descendant; parent.
single-user mode A startup mode that restricts connections. Only a single user can connect, and the CHECKPOINT mechanism (which guarantees that completed transactions are regularly written from the disk cache to the database device) is not started.
slice A subset of the data in a cube, specified by limiting one or more dimensions by members of the dimension. For example, facts for a particular year constitute a slice of multiyear data.
smalldatetime data type A SQL Server system data type that holds dates and times of day less precisely than datetime. Storage size is 4 bytes, consisting of one small integer for the number of days after January 1, 1900, and one small integer for the number of minutes past midnight. Dates range from January 1, 1900, through June 6, 2079, with accuracy to the minute.
smallint data type A SQL Server system data type that holds whole numbers from +32,767 through _32,768, inclusive. Storage size is 2 bytes.
smallmoney data type A SQL Server system data type that stores monetary values from +214,748.3647 through _214,748.3648 with accuracy to a ten-thousandth of a monetary unit. Storage size is 4 bytes. When smallmoney values are displayed, they are rounded up two places.
SMP See symmetric multiprocessor.
snap-in A program that runs within Microsoft Management Console (MMC) and that provides specific added functionality. The OLAP Manager is a snap-in. See also Microsoft Management Console (MMC); OLAP Manager.
Snapshot Agent The replication component that prepares snapshot files of published tables and stored procedures, stores the files on the Distributor, and records information about synchronization status in the distribution database.
snapshot cursor See static cursor.
snapshot replication A type of replication that takes a snapshot of current data in a publication at a Publisher and replaces the entire replica at a Subscriber on a periodic basis, in contrast to publishing changes when they occur. See also merge replication; transactional replication.
snowflake schema An extension of a star schema such that one or more dimensions are defined by multiple tables. In a snowflake schema, only primary dimension tables are joined to the fact table. Additional dimension tables are joined to primary dimension tables. See also star schema.
sort order A set of rules that determines how SQL Server compares, collates, and presents character data in response to database queries. Sort order is a serverwide setting that affects how strings are compared.
source database See publication database.
sparsity The relative percentage of a multidimensional structure's cells that do not contain data. OLAP Services stores only cells that contain data. A sparse cube requires less storage than a dense cube of identical structure design. See also data explosion; density.
SPID See server process ID.
SQL See structured query language (SQL).
SQL-92 The latest version of the standard for SQL, published in 1992. The international standard is ISO/IEC 9075:1992 Database Language SQL. The American National Standards Institute (ANSI) also published a corresponding standard (Data Language SQL X3.135-1192), so SQL-92 is sometimes referred to as ANSI SQL in the United States.
SQL-DMF SQL Distributed Management Framework. An integrated framework of objects, services, and components used to manage SQL Server. SQL-DMF lessens the need for user-attended maintenance tasks, such as database backup and alert notification, by providing services that interact directly with SQL Server. At its most basic level, SQL-DMF provides direct access to the SQL Server engine and services from the command line through Transact-SQL. The second tier of the framework is a set of distributed management objects (DMOs) that provides an object interface to the SQL Server engine and services. The top level of the framework is a graphical administration tool, SQL Server Enterprise Manager, which provides an easy way to manage a multiserver environment. The framework also provides services for replication, scheduling, and alerting.
SQL Executive See SQL Server Agent.
SQL Mail A component of SQL Server that includes extended stored procedures and allows SQL Server to send and receive mail messages through the built-in Windows NT mail application programming interface (MAPI). A mail message can consist of short text strings, the output from a query, or an attached file.
SQL script See script.
SQL Server Agent A service used to create and manage local or multiserver jobs, alerts, and operators. Job schedules are defined in the Job Properties dialog box. SQL Server Agent communicates with SQL Server to execute the job according to the job's schedule.
SQL Server Authentication A login security mode that allows users to connect to SQL Server using SQL Server logins. SQL Server performs the authentication.
SQL Server Books Online The SQL Server online documentation set. SQL Server Books Online is an installation option presented by the Setup program. If you select this option, files are copied to your hard disk, and the SQL Server Books Online icon is added to the Microsoft SQL Server 7.0 program group.
SQL Server Client Network Utility A utility whose most basic purpose is to change the default client Net-Library. The SQL Server Client Network Utility is also used for managing the client configuration for DB-Library, Net-Libraries, and custom-defined network connections.
SQL Server Enterprise Manager A graphical MMC snap-in that allows for easy, enterprise-wide configuration and management of SQL Server and SQL Server objects. You can also use SQL Server Enterprise Manager to manage logins, permissions, and users; create scripts; manage databases; back up databases and transaction logs; and manage tables, views, stored procedures, triggers, indexes, rules, defaults, and user-defined data types.
SQL Server Event Forwarding Server See forwarding server.
SQL Server login An account stored in SQL Server that allows users to connect to the SQL Server.
SQL Server Performance Monitor integration The integration of Windows NT Performance Monitor with SQL Server, providing up-to-the-minute activity and performance statistics.
SQL Server Profiler A SQL Server tool that captures a continuous record of server activity in real time. SQL Server Profiler can monitor many different server events and event categories, filter those events with user-specified criteria, and output a trace to the screen, a file, or another SQL Server.
SQL Server Query Analyzer A SQL Server utility that allows you to enter Transact-SQL statements and stored procedures in a graphical user interface. SQL Server Query Analyzer also provides capability for graphically analyzing queries.
SQL Server role A named set of security accounts. A SQL Server role can contain Windows NT users, Windows NT groups, SQL Server users, or other SQL Server roles from the same database.
SQL Server Service Manager A SQL Server utility that provides a graphical way to start, pause, and stop the MS DTC, MSSQLServer, and SQLServerAgent services. SQL Server is integrated with the service control management of Windows NT, so you can start, pause, and stop SQL Server, MS DTC, and SQLServer-Agent from the Services application in Control Panel or from the Server Manager application.
SQL Server user A security account that maps to a SQL Server login and controls the permissions on activities performed in a database.
SQL statement A SQL or Transact-SQL statement, such as SELECT or DELETE, that performs some action on data.
SQL Transfer Manager See Data Transformation Services (DTS).
standalone installation An installation of SQL Server on a computer that is not connected to a network. A standalone installation may be used to install SQL Server on a computer that will soon be but is not yet connected to a network (for example, one that does not yet have a network adapter card installed.) Or a standalone installation might be performed on a computer that is intended as a development system that will have no need for network connections.
standard security SQL Server 7 no longer uses standard security, although SQL Server may authenticate users under Mixed Mode.
star join A join between a fact table (typically a large fact table) and at least two dimension tables. The fact table is joined with each dimension table on a dimension key. SQL Server considers special index manipulation strategies on these queries to minimize access to the fact table.
An example of a schema participating in a star join query could be a sales table, the fact table (with millions of rows), a product table, with the description of several hundred products, and a store table with several dozen store names. (In this example, the product and store tables are dimension tables). A query for selecting sales data for a small set of stores and a subset of products restricted by attributes not present in the sales database is an ideal candidate for the star join query optimization.
star schema A relational database structure in which data is maintained in a single fact table at the center of the schema with additional dimension data stored in dimension tables. Each dimension table is directly related to the fact table by a key column. See also snowflake schema.
statement block See blocks.
statement permission Permission that controls the execution of Transact-SQL statements that create database objects or perform certain administrative tasks. Can be granted, revoked, or denied.
static cursor A cursor that shows the result set exactly as it was at the time the cursor was opened. Static cursors do not reflect updates, deletes, or inserts made to underlying data while the cursor is open. Sometimes called a snapshot cursor.
static SQL statement In Embedded SQL for C, a SQL statement that is built at the time the application is compiled. It is created as a stored procedure when the application is compiled, and the stored procedure is executed when the application is run.
statistics refresh The interval, in minutes and seconds, for refreshing SQL server statistics information. The default is 30 seconds.
status code A 4-byte integer that indicates the status of a result set returned to the client. The status code is sent to the client by using srv_senddone.
step object A Data Transformation Services (DTS) object that coordinates the flow of control and execution of tasks in a DTS package. A task that does not have an associated step object is never executed. See also data transformation; task object.
store-and-forward database See distribution database.
stored procedure A precompiled collection of Transact-SQL statements and optional control-of-flow statements stored under a name and processed as a unit. Stored procedures are stored within a database, can be executed with one call from an application, and allow user-declared variables, conditional execution, and other powerful programming features. SQL Server_supplied stored procedures are called system stored procedures. See also system stored procedure.
string functions Functions that perform operations on binary data, character strings, or expressions. Built-in string functions return values commonly needed for operations on character data.
structured query language (SQL) A database query and programming language originally developed by IBM for mainframe computers. It is widely used for accessing data and for querying, updating, and managing relational database systems. There is now an ANSI-standard SQL definition for all computer systems.
structured storage file See COM-structured storage file.
subquery A SELECT statement nested inside another SELECT, INSERT, UPDATE, or DELETE statement, or inside another subquery.
subscribe To agree to receive a publication. A destination database on a Subscriber subscribes to replicated data from a publication database on a Publisher.
Subscriber A server that receives copies of published data.
subscription database The database that receives tables and data replicated from a publication database.
surrogate key A unique identifier for a row within a database table. A surrogate, or candidate, key can be made up of one or more columns. By definition, every table must have at least one surrogate key (in which case it becomes the primary key for a table automatically). However, it is possible for a table to have more than one surrogate key (in which case one of them must be designated as the primary key). Any surrogate key that is not the primary key is called the alternate key.
symmetric multiprocessor A computer with more than one processor, where each processor can access memory, handle interrupts, and access I/O just like every other processor in the computer.
synchronization The process of maintaining the same schema and data in a publication at a Publisher and in the replica of a publication at a Subscriber. See also initial snapshot.
synchronous transaction A replication feature that allows a Subscriber to modify replicated data and send it to the Publisher by using two-phase commit. Synchronous transactions can be performed using either transactional replication or snapshot replication.
sysname A system-supplied user-defined data type that is a synonym for nvarchar(128) and is used to reference database object names.
system administrator The person responsible for the overall administration of a SQL Server. The system administrator (sa) login is the only login authorized to perform all functions in SQL Server. Certain critical administrative functions can be performed only by the sa login. Members of the sysadmin fixed server role operate outside the protection system (SQL Server does not check permission for these members). The members are also treated as the owner of whatever database they are using.
system catalog A collection of system tables found only in the master database. These tables describe server information such as logins and configuration options.
system databases Four databases that are provided on a newly installed SQL Server installation:
In addition, you can also install sample databases, pubs and Northwind, which are provided as learning tools and are the basis for most of the examples in the SQL Server documentation. Although installed by the Setup program, neither pubs nor Northwind are system databases, since SQL Server does not require them to operate.
system functions Functions that return specific information from the SQL Server installation. System functions allow access to database or server information from within an expression, such as from a WHERE clause or a SELECT statement.
system stored procedure A SQL Server_supplied, precompiled collection of Transact-SQL statements. System stored procedures are provided as shortcuts for retrieving information from system tables or as mechanisms for accomplishing database administration and other tasks that involve updating system tables. The names of all system stored procedures begin with sp_. System stored procedures are located in the master database and are owned by the system administrator, but many of them can be run from any database. If a system stored procedure is executed in a database other than master, it operates on the system tables in the database from which it is executed. You can write stored procedures (called user-defined stored procedures), which can be executed from any database.
system tables Tables that store SQL Server configuration information and definitions of all of the objects, users, and permissions in SQL Server databases. Server-level configuration information is stored in system tables found only in the master database. Every database contains system tables defining the users, objects, and permissions contained by the database.
The master database and its system tables are created during SQL Server Setup. System tables in a user database are created automatically when the database is created.
SQL Server contains system stored procedures to report and manage the information in system tables. Users should use these system stored procedures rather than accessing the system tables directly. Users should not directly update any system table.
T
table An object in a database that stores data as a collection of rows and columns.
table creation script See table schema script.
table data file A file containing a snapshot of the data of a published table used during synchronization as the source of data inserted into the destination table. The filename extension of a data snapshot is .BCP. The file is stored in the working folder of the distribution database, a subfolder in C:\Mssql7\Repldata by default. See also table schema script.
table-level constraint A constraint that allows various forms of data integrity to be defined on one column (column-level constraint) or on several columns (table-level constraint) when the table is defined or altered. Constraints support domain integrity, entity integrity, and referential integrity, as well as user-defined integrity.
table lock A lock on a table, including all data and indexes.
table scan The means by which SQL Server searches a table sequentially without using an index. SQL Server starts at the beginning of the table and reads every row in the table to find the rows that meet the search criteria of the query.
table schema script A script containing the schema of a published table used during synchronization to create the destination table. The filename extension of a schema script is .SCH. The file is stored in the working folder of the distribution database, a subfolder in C:\Mssql7\Repldata by default. See also table data file.
tabular data stream (TDS) The SQL Server internal client/server data transfer protocol. TDS allows client and server products to communicate regardless of operating system platform, server release, or network transport.
tape backup A backup operation to any tape device supported by Windows NT. If you are creating a tape backup file, you must first install the tape device by using Windows NT. The tape device must be physically attached to the SQL Server you are backing up.
task See job.
task object A Data Transformation Services (DTS) object that defines pieces of work to be performed as part of the data transformation process. For example, a task can execute a SQL statement or move and transform heterogeneous data from an OLE DB source to an OLE DB destination using the DTS data pump. See also data transformation; step object.
taskpad A graphical way of presenting actions that can be performed on a selected item in the console tree. In MMC, a taskpad is implemented as a view on the selected item in the console tree, and that view is represented as a DHTML page in the details pane.
TDS See tabular data stream (TDS).
tempdb database The database that provides a storage area for temporary tables, temporary stored procedures, and other temporary working storage needs. No special permissions are required to use tempdb (that is, to create temporary tables or to execute commands that may require storage space in the tempdb database). All temporary tables are stored in tempdb, regardless of what database the user who creates them is using.
temporary stored procedure A procedure placed in the temporary database, tempdb, and erased at the end of the session. A temporary stored procedure is created by prefacing the procedure name (in the CREATE statement) with a number sign—for example,
CREATE PROCEDURE #author_sel AS SELECT * FROM authors
The first 13 characters of a temporary stored procedure name (excluding the number sign) must be unique in tempdb. Because all temporary objects belong to the tempdb database, you can create a temporary stored procedure with the same name as a procedure already in another database.
temporary table A table placed in the temporary database, tempdb, and erased at the end of the session. A temporary table is created by prefacing the table name (in the CREATE statement) with a number sign—for example,
CREATE TABLE #authors (au_id Exchar (11))
The first 13 characters of a temporary table name (excluding the number sign) must be unique in tempdb. Because all temporary objects belong to the tempdb database, you can create a temporary table with the same name as a table already in another database.
text data type A SQL Server system data type specifying variable-length columns that can hold 2,147,483,647 characters. The text data type cannot be used for variables or parameters in stored procedures.
theta join A join based on a comparison of scalar values (=, > , >= , < , <= , < >, !<, !>).
thread A mechanism that allows one or more paths of execution through the same instance of an application. Each device requires one thread, and each remote site requires two threads. SQL Server uses the native thread services of Windows NT. There are separate threads for each network, a separate thread for database checkpoints, and a pool of threads for all users.
tight consistency A replication model that guarantees that all copies will be identical to the original. It is usually implemented using two-phase commit, and it requires a high-speed LAN. It also reduces database availability and is less scalable in its implementation than loose consistency.
Time dimension A dimension that breaks time down into levels such as Year, Quarter, Month, and Day. In OLAP Services, a special type of dimension created from a date/time column.
timestamp data type A SQL Server system data type that is a monotonically increasing counter whose values are always unique within a database. A timestamp is the date and time the data was last modified.
tinyint data type A SQL Server system data type that holds whole numbers from 0 through 255, inclusive. Storage size is 1 byte.
tool A SQL Server application with a graphical user interface used to perform common tasks.
total errors The number of errors that SQL Server detected while reading and writing.
total reads The number of disk reads made by SQL Server.
total writes The number of disk writes made by SQL Server.
trace file A file used by SQL Server Profiler to record monitored events.
transaction A group of database operations combined into a logical unit of work that is either wholly committed or rolled back. A transaction is atomic, consistent, isolated, and durable.
transactional replication A type of replication that marks selected transactions in the Publisher's database transaction log for replication and then distributes them asynchronously to Subscribers as incremental changes, while maintaining transactional consistency. See also merge replication; snapshot replication.
transaction log A database file in which all changes to the database are recorded. It is used by SQL Server during automatic recovery.
transaction processing A processing method in which transactions are executed immediately after they are received by the system.
transaction rollback Rollback of a user-specified transaction to the last savepoint inside a transaction or to the beginning of a transaction.
Transact-SQL The standard language for communicating between applications and SQL Server. The Transact-SQL language is an enhancement to structured query language (SQL), the ANSI-standard relational database language. It provides a comprehensive language for defining tables; for inserting, updating, or deleting information stored in tables; and for controlling access to data in those tables. Extensions such as stored procedures make Transact-SQL a full programming language.
Transact-SQL cursor A server cursor defined by using the Transact-SQL DECLARE CURSOR syntax. Transact-SQL cursors are intended for use in Transact-SQL batches, stored procedures, and triggers.
transformation See data transformation.
trigger A stored procedure that executes automatically when data in a specified table is modified. Triggers are often created to enforce referential integrity or consistency among logically related data in different tables.
trusted connection An authenticated connection between a client and a server. Windows NT Authentication requires network protocols that support trusted connections.
T-SQL See Transact-SQL.
tuple An ordered collection of members from different dimensions. For example, (Boston, [1995]) is a tuple formed by members of two dimensions: geography and time. A single member is a degenerated case of a tuple and can be used as an expression without the parentheses. For more information about tuples, see your OLE DB documentation. See also axis.
two-phase commit A protocol that ensures that transactions that apply to more than one server are completed on all servers or on none.
type conversion function A function that transforms expressions from one data type into another.
U
unattended installation A process that allows you to install SQL Server 7 without having to respond to prompts for information from the Setup program. Instead, you create an initialization file, save the initialization file on a storage device accessible to the computer that will be set up, and start Setup using some required options. During Setup, the configuration parameters are read from the initialization file.
UNC See universal naming convention (UNC).
underlying object An object (a table or another view) from which a view is derived. A view can have more than one underlying object.
underlying table A table from which a view is derived. A view can have more than one underlying table or underlying view. Also called a base table.
unenforced relationship A link between tables that references the primary key in one table to a foreign key in another table, and which does not check the referential integrity during INSERT and UPDATE transactions. An unenforced relationship is represented in a database diagram by a dashed line.
unhandled event forwarding server See forwarding server.
Unicode A set of letters, numbers, and symbols that SQL Server recognizes in the nchar, nvarchar, and ntext data types. It is related to but separate from character sets. Unicode has more than 65,000 possible values compared to a character set's 256, and takes twice as much space to store. Unicode includes characters for most languages.
Unicode collation A sort order for Unicode data. It is a set of rules that determines how SQL Server compares, collates, and presents Unicode data in response to database queries.
Unicode format Data stored in a bulk copy data file using Unicode characters.
Union query A query that combines two tables by performing the equivalent of appending one table to the other.
UNIQUE constraints Constraints that enforce entity integrity on a nonprimary key. UNIQUE constraints ensure that no duplicate values are entered and that an index is created to enhance performance.
uniqueidentifier data type A data type containing a unique identification number stored as a 16-byte binary string, used for storing a globally unique identifier (GUID).
unique index An index in which no two rows are permitted to have the same index value, thus prohibiting duplicate index or key values. The system checks for duplicate key values when the index is created and checks each time data is added with an INSERT or UPDATE statement.
universal naming convention (UNC) A naming convention that consists of the following format:
\\servername\sharename\path \file_name
unrestricted publication In replication, a security status. A publication marked Unrestricted (the default) can be subscribed to by any registered Subscriber. See also restricted publication.
update An addition, deletion, or change to data.
update lock A lock placed on resources (such as rows, pages, or tables) that can be updated. Update locks are used to prevent a common form of deadlock that occurs when multiple sessions are locking resources and are potentially updating them later.
Update query A query that changes the column values of one or more rows in a table.
update replication Any replication technology that allows you to update replicated data. See also merge replication; synchronous transaction.
update statistics A process that recalculates information about the distribution of key values in specified indexes. These statistics are used by the query optimizer to determine the most efficient way to execute a query.
user (account) Used to control permissions for activities performed in a database. User accounts are created in a database and assigned to a login ID for allowing a user to access that database. The abilities a user has within a database depend on the permissions granted to the user account and on the permissions granted to any roles of which the user account is a member. A user account name can have up to 128 characters and must be unique within the database. The characters can be alphanumeric, but the first character must be a letter, the number sign (#), or an underscore (_) (for example, #CHRIS or USER8). A user account is also called a username or a user ID.
user databases A database created by a user. Each user database is created with a copy of the tables from the model database. The system tables in a user database are copied from the model database automatically when a database is created.
user-defined data type A data type, based on a system-supplied SQL Server data type, created by the user for custom data storage. Rules and defaults can be bound to user-defined data types (but not to system data types). See also base data type.
user-defined event A server process created internally by Open Data Services and not as the result of a client action. The srv_define_event function creates a user-defined event.
username A name known to a database and assigned to a login ID for the purpose of allowing a user to access that database. The abilities a user has within a database depend on the permissions granted to the username as well as to any groups of which the username is a member. A username can have up to 128 characters and must be unique within the database. The characters can be alphanumeric, but the first character must be a letter or the symbols # or _ (for example, #CHRIS or USER8).
utility A SQL Server application run from a command prompt to perform common tasks.
V
value expression A multidimensional expression (MDX) that returns a value. Value expressions can operate on sets, tuples, members, levels, numbers, or strings. For example, set value expressions operate on member, tuple, and set elements to yield other sets. For more information about MDX, see your OLE DB documentation.
varbinary data type A SQL Server system data type that holds up to 8000 bytes of variable-length binary data.
varchar data type A SQL Server system data type that holds any combination of up to 8000 letters, symbols, and numbers.
variables Defined entities that are assigned values. A local variable is defined with a DECLARE @localvariable statement and assigned an initial value within the statement batch where it is declared with either a SELECT or SET @localvariable statement.
vector aggregate Functions applied to all rows that have the same value in a specified column or expression by using the GROUP BY clause and, optionally, the HAVING clause (producing a value for each group per function).
vertical filtering To create an article that replicates only selected columns from the base table. Subscribers receive only the subset of vertically filtered data. The primary key column(s) in a table cannot be filtered out of an article in a transactional publication. You can use vertical filtering to partition your base table vertically. See also horizontal filtering; vertical partitioning.
vertical partitioning To segment a single table into multiple tables based on selected columns. Each of the multiple tables has the same number of rows but fewer columns. See also horizontal filtering; vertical filtering.
view An alternate way of looking at data from one or more tables in the database. A view is a virtual table, usually created as a subset of columns from one or more tables, which is expressed as a SELECT statement. Depending on the definition, data in base tables can be modified through views.
virtual cube A logical cube composed of dimensions and measures of one or more physical cubes. Virtual cubes are similar to views in a relational database. Virtual cubes combine data from the underlying physical cubes and require no additional data storage.
virtual dimension A logical dimension based on the properties of members of a physical dimension. Members of a virtual dimension are derived from the values of one of the properties of a member of the physical dimension. For example, a virtual dimension Color could be derived from a product dimension containing member properties Color, Size, and Style; it could contain members Blue, Red, and Green, which are values for the property Color. See also dimension; member; member property.
virtual log file A segment of a transaction log file. Each transaction log file is divided logically into virtual log files. Virtual log files are the unit of truncation for the transaction log. When a virtual log file no longer contains log records for active transactions, it can be truncated and the space becomes available to log new transactions.
W
wildcard characters Characters, including underscore (_), percent (%), and brackets ([ ]), used with the LIKE keyword for pattern matching.
Windows Distributed interNet Applications Architecture (Windows DNA) The all-encompassing application architecture used by Microsoft Corporation.
Windows NT Authentication A login security mode that allows users to connect to SQL Server through a Windows NT user account.
Windows NT Event Viewer A Windows NT application that allows you to view events, filter certain events, and retain event logs.
Windows NT File System (NTFS) An advanced file system designed for use specifically within the Windows NT operating system. It supports file system recovery, extremely large storage media, long filenames, and various features for the Portable Operating System Interface for Unix (POSIX) subsystem. It also supports object-oriented applications by treating all files as objects with user-defined and system-defined attributes.
Windows NT Performance Monitor A Windows NT utility that provides a way for system administrators to monitor the performance of SQL Server. SQL Server statistics include lock performance, current size of transaction logs, user connections, and server performance. You can even set alerts to initiate a specified action when a specified threshold is reached.
Windows NT user A security account that maps to a Windows NT login and controls permissions on activities performed in a database.
wizard A series of pages, displayed in a secondary window, that automates tasks. A wizard is generally used to help you perform complex or infrequent tasks.
word generation The process of determining other forms of the word(s) specified. The Microsoft Search Service currently implements inflectional word generation. For example, if the word swim is specified, SQL Server also searches for swim, swam, and swimming.
write-ahead log A transaction logging method in which the log is always written prior to the data.
write-back The facility that enables users to apply changes to data in a cube. User-initiated changes to cube data are logged to a separate partition table associated with the cube and applied automatically as cube data is viewed. To the user it appears as if the data in the cube has changed.
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