Source: CAE specification, Structured Query Language (SQL), Version 2.
X/Open document number: C449. ISBN: 1-85912-151-9.
X/Open-95 SQL is based closely on the International Standard for the Database Language SQL, ISO 9075:1992, ('SQL-92') and includes some extensions to the International Standard which reflect the capabilities of current implementations.
This version of the standard specifically incorporates the following features:
- New table combination operations (JOIN variants and use of UNION in CREATE VIEW).
- Referential ON DELETE actions for the CREATE TABLE statement, which define how database integrity should be maintained if row deletion causes violation of FOREIGN KEY constraints.
- New features and exceptions relating to the CAST function.
- Various operations on fixed and variable length character strings, including the concatenation operator and the scalar functions CHAR_LENGTH, SUBSTRING and TRIM.
- Inclusion of DATE, TIME, TIMESTAMP and INTERVAL named data types.
- New form of ALTER TABLE allowing for the dropping and adding of columns.
- Support for four isolation levels through the SET TRANSACTION statement.
- Support for the SET CATALOG and SET SCHEMA statements.
- Enhancements to PRIMARY KEY, allowing UNIQUE constraints on columns containing null values.
- New system views COLUMN_PRIVILEGES, INDEXES, SCHEMATA, TABLE_PRIVILEGES, USAGE_PRIVILEGES and VIEWS.
- The keyword AS is permitted in correlation names, the keyword TABLE in the GRANT and REVOKE statements, the keyword FROM in the FETCH statement and the keyword WORK becomes optional in COMMIT and ROLLBACK.
- Enhancements to GET DIAGNOSTICS allowing the type of the relevant SQL statement to be determined.
- Enhancements to the INSERT statement relating to how values are specified.
- Internationalization features relating to support for national character sets and collations.
- Addition of the string functions LOWER, UPPER and POSITION.
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