S

satellite

A DB2 UDB server that is a member of a group of similar DB2 UDB servers. Each satellite in the group runs the same application and has a similar configuration to support the application.

Satellite Administration Center

A user interface that provides centralized administrative support for satellites.

satellite control server

A DB2 UDB system that contains the satellite control database, SATCTLDB.

savepoint

A named entity that represents the state of data and schemas at a particular point in time within a unit of work.

savepoint level

A distinct scope that is used for reference and interaction between savepoint-related statements.

SBCS

See [single-byte character set]

scalar fullselect

A fullselect that returns a single valueone row of data that consists of exactly one column.

scalar function

A function that optionally accepts arguments and returns a single scalar value each time it is invoked. A scalar function can be referenced in an SQL statement wherever an expression is valid.

scale

The number of digits in the fractional part of a number.

schema

A collection of database objects such as tables, views, indexes, or triggers that define a database. A database schema provides a logical classification of database objects.

scrollable cursor

A cursor that can be moved in both a forward and a backward direction.

scrollable result set

A result set associated with a scrollable cursor that allows the application to fetch rows and to fetch previously fetched rows again.

search

To request the display of objects that meet user-specified criteria.

search condition

A criterion for selecting rows from a table. A search condition consists of one or more predicates.

secondary log

A set of one or more log files used to record changes to a database. Storage for these files is allocated as needed when the primary log is full.

section

The segment of a plan or package that contains the executable structures for a single SQL statement. For most SQL statements, one section in the plan exists for each SQL statement in the source program. However, for cursor-related statements, the DECLARE, OPEN, FETCH, and CLOSE statements reference the same section because they each refer to the SELECT statement named in the DECLARE CURSOR statement. SQL statements such as COMMIT, ROLLBACK, and some SET statements do not use a section.

self-referencing constraint

A referential constraint that defines a relationship in which a table is a dependent of itself.

self-referencing row

A row that is a parent of itself.

self-referencing subquery

A subselect or fullselect within a DELETE, INSERT, or UPDATE statement referring to the same table that is the object of the SQL statement.

self-referencing table

A table that is both a parent and dependent table in the same referential constraint.

sequence

A database object independent of any one table that automatically generates unique key values based on initial user specifications.

sequential prefetch

A mechanism that triggers consecutive asynchronous I/O operations. Pages are fetched before they are required, and several pages are read with a single I/O operation.

serialization

(1) The consecutive ordering of items.

(2) The process of controlling access to a resource to protect the integrity of the resource.

server

In a network, hardware or software that provides facilities to other stations, for example, a file server, a printer server, or a mail server.

service name

A name that provides a symbolic method of specifying the port number to be used at a remote node. The TCP/IP connection requires the address of the remote node and the port number to be used on the remote node to identify an application.

set operator

The SQL operators UNION, EXCEPT, and INTERSECT that correspond to the relational operators union, difference, and intersection. A set operator derives a result table by combining two other result tables.

shared memory

Shared memory is an efficient means of passing and sharing data between programs/processes. One program or process will create a memory portion which other processes (if permitted) can access.

single-byte character set (SBCS)

A character set in which each character is represented by a one-byte code.

single-precision floating point number

A 32-bit approximate representation of a real number.

slice

The set of blocks that contain pages with data having a certain value of one of the clustering dimensions.

SMS table space

See system-managed space table space.

SNA

See [Systems Network Architecture]

snapshot

A record of the current state of the database environment.

socket

A communications handle used by TCP/IP.

soft checkpoint

The process of writing some information to the log file header. This information determines the starting point in the log if a database restart is required.

source program

A set of host language statements and SQL statements processed by an SQL precompiler.

source table

A table that can be a base table, a view, a table expression, or a user-defined table function.

source type

An existing type that internally represents a distinct type.

special register

DB2 special registers are memory registers that allow DB2 to provide information to an application about its environment. They can be referenced in SQL statements. Examples are USER and CURRENT DATE.

SQL

See [Structured Query Language]

SQL Assistant

A wizard that is available in several DB2 UDB tools and centers that generates SQL statements graphically.

SQLCA

See [SQL communication area]

SQL communication area (SQLCA)

A set of variables that provides an application program with information about the execution of its SQL statements or its requests from the database manager.

SQL connection

An association between an application process and a local or remote application server.

SQLDA

See [SQL descriptor area]

SQL descriptor area (SQLDA)

(1) A set of variables that is used in the processing of certain SQL statements. The SQLDA is intended for dynamic SQL programs.

(2) A structure that describes input variables, output variables, or the columns of a result table.

SQL escape character

The symbol that is used to enclose an SQL delimited identifier. The escape character is the quotation mark, except in COBOL applications, where the user assigns the symbol to be either a quotation mark or an apostrophe.

SQL function

A function that is implemented entirely by using a subset of SQL statements and SQL PL statements.

SQLJ

A three-part standard for supporting embedded SQL in Java programs (Part 0), defining and calling Java stored procedures and user-defined functions (Part 1), and using database structured types in Java (Part 2).

SQL method

A method that is implemented entirely by using a subset of SQL statements and SQL PL statements.

SQL PL

See [SQL procedural language]

SQL procedural language (SQL PL)

A language extension of SQL that consists of statements and language elements to implement procedural logic in SQL statements. SQL PL provides statements for declaring variables and condition handlers, assigning values to variables, and for implementing procedural logic.

SQL procedure

A procedure that is created by running the CREATE PROCEDURE statement and is implemented entirely in SQL PL. An SQL procedure is called by running the CALL statement.

SQL return code

Either SQLCODE or SQLSTATE.

standard database

In High Availability Disaster Recovery (HADR), a database that is neither the primary nor the standby. A standard database is not configured for HADR.

standby database

In High Availability Disaster Recovery (HADR), a copy of the primary database. Updates to this database occur by rolling forward log data that is generated on the primary database and sent to the standby database.

star schema

A type of relational database schema that is composed of a set of tables comprised of a single, central fact table surrounded by dimension tables. Star schemas are used by the DB2 OLAP Server and are often created in the Data Warehouse Center.

statement

An instruction in a program or procedure.

statement savepoint

An internal savepoint mechanism that ensures that either all the updates or none of the updates are applied to the database at the completion of an SQL statement.

static SQL

SQL statements that are embedded within a program and are prepared during the program preparation process before the program is executed. After being prepared, a static SQL statement does not change, although values of host variables specified by the statement can change.

statistics profile

A file that contains all of the options information that specifies which statistics are collected for a table when using a particular RUNSTATS command logic.

stored procedure

(1) An application program, possibly containing SQL statements, that can be invoked with the SQL CALL statement.

(2) A user-written application program that can be started by using the SQL CALL statement.

string

A sequence of bytes that might represent characters.

strong typing

A process guarantying that only user-defined functions and operations defined on a distinct type can be applied to that type. For example, two currency types, such as Canadian dollars and U.S. dollars, cannot be directly compared, but a user-defined function can be provided to convert one currency to the other and then do the comparison.

structure

A name that refers collectively to different types of DB2 UDB objects, such as tables, databases, views, indexes, and table spaces.

Structured Query Language (SQL)

A standardized language for defining and manipulating data in a relational database.

structured type

A data type that is a named collection of attributes (standard data types or other structured types), which allows for greater semantic control than predefined types.

subagent

A type of agent that works on subrequests. A single application can make many requests, and each request can be broken into many subrequests. Therefore, there can be multiple subagents that work on behalf of the same application. All subagents working for the application are initiated by the initiating agent for that application.

subordinate agent

See [subagent]

subquery

A SELECT statement within the WHERE or HAVING clause of another SQL statement; a nested SQL statement.

subselect

The form of a query that does not include an ORDER BY clause, an UPDATE clause, or UNION operators.

subset

To replicate data from part of a source table, rather than from the entire table, to a target table. Data can be subset by rows or by columns.

summary table

A specialized type of materialized query table whose fullselect contains a GROUP BY clause that summarizes data from the tables referenced in the fullselect.

superuser

A user who has various system control authorities above and beyond that of the ordinary user. In UNIX environments, the standard superuser is root.

sync point

See [point of consistency]

synchronous

Pertaining to two or more processes that depend on the occurrences of specific events, such as a common timing signal.

system administrator

(1) The person at a computer installation who designs, controls, and manages the use of the computer system.

(2) A DB2 UDB user with SYSADM authority.

system authority

SYSCTRL and SYSMAINT authority levels with full privileges for managing the system but without the ability to access the data.

system catalog

See [catalog]

system database directory

A directory containing entries for every database that can be accessed using the database manager. The directory is created when the first database is created or cataloged on the system.

system-managed space (SMS) table space

A table space whose space is managed by the operating system. This storage model is based on files that are created under subdirectories and managed by the file system.

system monitor

See [database system monitor]

Systems Network Architecture (SNA)

An architecture that describes the logical structure, formats, protocols, and operational sequences for transmitting information units through networks, and also operational sequences for controlling the configuration and operation of networks.