как говорит Oracle:

pomah 26.06.2002 15:19

Oracle Corporation strives to comply with industry-accepted standards and participates actively in SQL standards committees. Industry-accepted committees are the American National Standards Institute (ANSI) and the International Standards Organization (ISO), which is affiliated with the International Electrotechnical Commission (IEC). Both ANSI and the ISO/IEC have accepted SQL as the standard language for relational databases. When a new SQL standard is simultaneously published by these organizations, the names of the standards conform to conventions used by the organization, but the standards are technically identical.

The latest SQL standard was adopted in July 1999 and is often called SQL-99. The formal names of this standard are:

* ANSI X3.135-1999, "Database Language SQL", Parts 1 ("Framework"), 2 ("Foundation"), and 5 ("Bindings")

* ISO/IEC 9075:1999, "Database Language SQL", Parts 1 ("Framework"), 2 ("Foundation"), and 5 ("Bindings")

SQL-99 replaced the previous version of the standard, commonly known as SQL-92. SQL-99 is an upward compatible extension of SQL-92, except for a few minor incompatibilities noted in Annex E of Part 2, "Foundation," of SQL-99.

SQL-92 defined four levels of compliance: Entry, Transitional, Intermediate, and Full. A conforming SQL implementation must support at least Entry SQL. Oracle8i fully supports Entry SQL as outlined in Federal Information Processing Standard (FIPS) PUB 127-2, and has many features that conform to Transitional, Intermediate, or Full SQL.

The minimal conformance level for SQL-99 is known as Core. Core SQL-99 is a superset of SQL-92 Entry Level specification. Oracle8i also is broadly compatible with the SQL-99 Core specification. However, some SQL-99 Core features are not currently implemented in Oracle8i or differ from the Oracle8i implementation. Oracle Corporation is committed to fully supporting SQL-99 Core functionality in a future release, while providing upward compatibility for existing applications.