SQL-92 (also called SQL 2) was the third revision of the
SQL
Structured Query Language (SQL) (pronounced ''S-Q-L''; or alternatively as "sequel")
is a domain-specific language used to manage data, especially in a relational database management system (RDBMS). It is particularly useful in handling s ...
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
A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve informa ...
. 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
Christopher John Date (born 18 January 1941) is a British independent author, lecturer, researcher and consultant, specialising in relational database theory.
Biography
Chris Date attended High Wycombe Royal Grammar School from 1951 to 1958 an ...
with Hugh Darwen
Hugh Darwen is a computer scientist who was an employee of IBM United Kingdom from 1967. to 2004, and has been involved in the development of the relational model.
Work
From 1978 to 1982 he was a chief architect on Business System 12, a dat ...
: ''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
In formal language theory and computer science, a substring is a contiguous sequence of characters within a string. For instance, "''the best of''" is a substring of "''It was the best of times''". In contrast, "''Itwastimes''" is a subsequenc ...
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)
The syntax of the SQL programming language is defined and maintained by ISO/IEC SC 32 as part of ''ISO/IEC 9075''. This standard is not freely available. Despite the existence of the standard, SQL code is not completely portable among different d ...
.
* Support for alterations of
schema definitions via
ALTER and
DROP.
* Bindings for
C,
Ada
Ada may refer to:
Arts and entertainment
* '' Ada or Ardor: A Family Chronicle'', a novel by Vladimir Nabokov
Film and television
* Ada, a character in 1991 movie '' Armour of God II: Operation Condor''
* '' Ada... A Way of Life'', a 2008 Bollywo ...
, 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
The Call Level Interface (CLI or SQL/CLI) is an application programming interface (API) and software standard to embed Structured Query Language (SQL) code in a host program as defined in a joint standard by the International Organization for Stand ...
(
Call Level Interface
The Call Level Interface (CLI or SQL/CLI) is an application programming interface (API) and software standard to embed Structured Query Language (SQL) code in a host program as defined in a joint standard by the International Organization for Stand ...
) in 1995
*
SQL/PSM
SQL/PSM (SQL/Persistent Stored Modules) is an ISO standard mainly defining an extension of SQL with a procedural language for use in stored procedures. Initially published in 1996 as an extension of SQL-92 (ISO/IEC 9075-4:1996, a version sometimes ...
(
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