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SQL-92. First published. November 1992. Domain. SQL. SQL-92 was the third revision of the SQL database query language. Unlike SQL-89, it was a major revision of the standard. Aside from a few minor incompatibilities, the SQL-89 standard is forward-compatible with SQL-92. The standard specification itself grew about five times compared to SQL-89.
The ANSI/ISO standard SQL 92 refers to three different read phenomena when a transaction retrieves data that another transaction might have updated. In the following examples, two transactions take place.
The SQL:1999 standard calls for a Boolean type, but many commercial SQL servers (Oracle Database, IBM Db2) do not support it as a column type, variable type or allow it in the results set. Microsoft SQL Server is one of the few database systems that properly supports BOOLEAN values using its "BIT" data type [ citation needed ] .
Snapshot isolation has been used to criticize the ANSI SQL-92 standard's definition of isolation levels, as it exhibits none of the "anomalies" that the SQL standard prohibited, yet is not serializable (the anomaly-free isolation level defined by ANSI).
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
The SQL:2003 standard makes minor modifications to all parts of SQL:1999 (also known as SQL3), and officially introduces a few new features such as: [1] XML -related features ( SQL/XML) Window functions. the sequence generator, which allows standardized sequences. two new column types: auto-generated values and identity-columns.
SQL:2011 or ISO/IEC 9075:2011 (under the general title "Information technology – Database languages – SQL") is the seventh revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2011. The standard consists of 9 parts which are described in detail in SQL.
The ANSI SQL-92 standard includes the COALESCE function implemented in Oracle, [21] SQL Server, [22] PostgreSQL, [23] SQLite [24] and MySQL. [25] The COALESCE function returns the first argument that is not null.