Appendix F. Glossary

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Sams Teach Yourself SQL in 24 Hours, Third Edition
By Ronald R. Plew, Ryan K. Stephens
Table of Contents
Part IX.  Appendixes


alias

Another name or term for a table or column.



ANSI

American National Standards Institute.



application

A set of menus , forms, reports , and code that performs a business function using a database.



buffer

An area in memory for editing or execution of SQL.



Cartesian product

The result of not joining tables in the WHERE clause of a SQL statement. When tables in a query are not joined, every row in one table is paired with every row in all other tables.



client

The client is typically a PC, but can be another server that is dependent on another computer for data, services, or processing. A client application enables a client machine to communicate with a server.



column

A part of a table that has a name and a specific data type.



COMMIT

Makes changes to data permanent.



composite index

An index that is composed of two or more columns .



condition

Search criteria in a query's WHERE clause that evaluates to TRUE or FALSE.



constant

A value that does not change.



constraint

Restrictions on data that are enforced at the data level.



cursor

A work area in memory where the current SQL statement is stored.



data dictionary

Another name for the system catalog.

See also [system catalog]


data type

Defines data as a type, such as number, date, or character.



database

A collection of data.



DBA

Database Administrator. An individual who manages a database.



DDL

Data Definition Language.



default

A value used when no specification has been made.



distinct

Unique; used in the SELECT clause to return unique values.



DML

Data Manipulation Language.



domain

An object that is associated with a data type to which constraints may be attached; similar to a user -defined type.



DQL

Data Query Language.



end user

Users whose jobs require them to query or manipulate data in the database. The end user is the individual for which the database exists.



field

Another name for a column in a table.

See also [column]


foreign key

One or more columns whose values are based on the primary key column values in another table.



full table scan

The search of a table from a query without the use of an index.



function

An operation that is predefined and can be used in a SQL statement to manipulate data.



GUI

Graphical User Interface.



host

The computer on which a database is located.



index

Pointers to table data that make access to a table more efficient.



JDBC

Java Database Connectivity. Software that allows a Java program to communicate with a database in order to process data.



join

Combines data from different tables by linking columns. Used in the WHERE clause of a SQL statement.



key

A column or columns that identify rows of a table.



normalization

Designing a database to reduce redundancy by breaking large tables down into smaller, more manageable tables.



NULL value

A value that is unknown.



objects

Elements in a database, such as triggers, tables, views, and procedures.



ODBC

Open Database Connectivity is software that allows for standard communication with a database. ODBC is typically used for inter-database communication between different implementations , and for communication between a client application and a database.



operator

A reserved word or symbol used to perform an operation, such as addition or subtraction.



optimizer

Internal mechanism of the database (consists of rules and code) that decides how to execute a SQL statement and return an answer.



parameter

A value or range of values that is used to resolve a part of a SQL statement or program.



primary key

A specified table column that uniquely identifies rows of the table.



privilege

Specific permissions that are granted to users to perform a specific action in the database.



procedure

A set of instructions that are saved for repeated calling and execution.



public

A database user account that represents all database users.



query

A SQL statement that is used to retrieve data from a database.



record
See [row]
referential integrity

Assures that values from one column depend on the values from another column. Referential integrity is normally used between two tables, but in some tables, can be used so that a table references itself. A self-referenced table is referred to as a recursive relationship.



relational database

A database that is organized into tables that consist of rows, which contain the same sets of data items, where tables in the database are related to one another through common keys.



role

A database object that is associated with a group of system and/or object privileges, used to simplify security management.



ROLLBACK

A command that undoes all transactions since the last COMMIT or SAVEPOINT command was issued.



row

Sets of records in a table.



savepoint

A specified point in a transaction to which you can roll back or undo changes.



schema

A set of related objects in a database owned by a single database user.



security

The process of ensuring that data in a database is fully protected at all times.



SQL

Structured Query Language.



stored procedure

SQL code that is stored in a database and ready to execute.



subquery

A SELECT statement embedded within another SQL statement.



synonym

Another name given to a table or view.



syntax for SQL

A set of rules that shows mandatory and optional parts of a SQL statement's construction.



system catalog

Collection of tables or views that contain information about the database.



table

The basic logical storage unit for data in a relational database.



transaction

One or more SQL statements that are executed as a single unit.



trigger

A stored procedure that executes upon specified events in a database, such as before or after an update of a table.



user-defined type

A data type that is defined by a user, which can be used to define table columns.



variable

A value that does not remain constant.



view

A database object that is created from one or more tables and can be used the same as a table. A view is a virtual table that has no storage requirements of its own.




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Sams Teach Yourself SQL in 24 Hours
Sams Teach Yourself SQL in 24 Hours (5th Edition) (Sams Teach Yourself -- Hours)
ISBN: 0672335417
EAN: 2147483647
Year: 2002
Pages: 275

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