SQL-92 (also called SQL 2) was the third revision of the
SQL database
In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...
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. Much of it was due to more precise specifications of existing features; the increase due to new features was only by a factor of 1.5–2. Many of the new features had already been implemented by vendors before the new standard was adopted.
However, most of the new features were added to the "intermediate" and "full" tiers of the specification, meaning that conformance with SQL-92 entry level was scarcely any more demanding than conformance with
SQL-89.
The next revision is
SQL:1999 (SQL3).
Related official standard
* ANSI X3.135-1992
* ISO/IEC 9075:1992
* FIPS PUB 127-2
New features
Significant new features include:
[ C. J. Date with Hugh Darwen: ''A Guide to the SQL standard : a users guide to the standard database language SQL, 4th ed.'', Addison Wesley, USA 1997, ]
* New data types defined:
DATE,
TIME,
TIMESTAMP,
INTERVAL,
BIT string,
VARCHAR strings, and
NATIONAL CHARACTER strings.
* Support for additional
character set
Character encoding is the process of assigning numbers to graphical characters, especially the written characters of human language, allowing them to be stored, transmitted, and transformed using computers. The numerical values that make up a c ...
s beyond the base requirement for representing SQL statements.
* New scalar operations such as string concatenation and
substring extraction, date and time mathematics, and conditional statements.
* New set operations such as
UNION,
UNION ALL,
CROSS JOIN, and formalized
JOIN types (
INNER JOIN,
LEFT JOIN,
RIGHT JOIN,
FULL OUTER JOIN).
* Conditional expressions with
CASE. For an example, see
Case (SQL).
* Support for alterations of
schema definitions via
ALTER and
DROP.
* Bindings for
C,
Ada, and
MUMPS
MUMPS ("Massachusetts General Hospital Utility Multi-Programming System"), or M, is an imperative, high-level programming language with an integrated transaction processing key–value database. It was originally developed at Massachusetts Gen ...
.
* New features for user privileges.
* New integrity-checking functionality such as within a
CHECK constraint.
* A new ''information schema''—read-only views about database metadata like what tables it contains, etc. For example,
SELECT * FROM INFORMATION_SCHEMA.TABLES;.
* Dynamic execution of queries (as opposed to prepared).
* Better support for remote database access.
* Temporary tables;
CREATE TEMP TABLE etc.
*
Transaction isolation levels.
* New operations for changing data types on the fly via
CAST (expr AS type).
*
Scrolled cursors.
* Compatibility flagging for backwards and forwards compatibility with other SQL standards.
Extensions
Two significant extensions were published after standard (but before the next major iteration.)
*
SQL/CLI (
Call Level Interface) in 1995
*
SQL/PSM (
stored procedure
A stored procedure (also termed prc, proc, storp, sproc, StoPro, StoredProc, StoreProc, sp, or SP) is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database d ...
s) in 1996
References
External links
The SQL-92 standard
{{SQL
*
Declarative programming languages
Programming languages created in 1992