This standard specifics the syntax and semantics of two database languages:
1) A schema definition language (SQL-DDL), for dcclaring thc structurcs and integrity constraints of an SQL database.
2) A module language and a data manipulation language (SQL-DML), for dcclaring the database procedures and executable statements of a specific database application program.
This standard defines thc logicai data structurcs and basic operations for an SQL database. It provides functional capabilities for designing, accessing, maintaining, controlling, and protecting thc database.
This standard provides a vehicle for portability of database definitions and application programs between confonning implcmcntations.
This standard specifics two levels and a separate integrity cnhanccment feature. I cvel 2 is the complete SQL database language excluding thc integrity enhanecment feature. I?vcI 1 is thc subsct of I?vcI 2 defined in clause 9, "Levels" on page 99.
NOTE: Additional SQL language is planned for laler addenda to this standard. Major topics under consider-ation for such addenda include enhanced transaclion management, specification of certain implementor-defined rules, enhanced character handling facilities, and support for national character sets.
The integrity enhancement feature compriscs a means of specifying:
1) referential constraints between tables, which have to be satisfied;
2) check constraints to be applicd to the rows of a table; and,
3) a default value for a column when a row is inserted into a table.
Annexes to this standard specify embedded syntax for including SQL data manipulation language statements in an otherwise standard application program. Such embedded syntax is defined to be a shorthand notation for a standard application program in which the embedded SQL statements have been rcplaced with expiicit "calls" of database procedures that contain thc SQL- statements.
This standard applies to implcmcntations that exist in an environment that may include application programming languages, end-uscr qucry languages, report generator systems, data dictionary systems, program
library systems, and distributed communication systems, as well as various tools for database design, data administration, and performance optimization.