SQL-92 was the third revision of the
SQL database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases ...
query language
Query languages, data query languages or database query languages (DQL) are computer languages used to make queries in databases and information systems. A well known example is the Structured Query Language (SQL).
Types
Broadly, 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.
Later revisions of the standard include
SQL:1999 (SQL3),
SQL:2003,
SQL:2008,
SQL:2011 and
SQL:2016.
New features
Significant new features include:
C. J. Date
Chris Date (born 1941) is an independent author, lecturer, researcher, and consultant, specializing in relational database theory.
Biography
Chris Date attended High Wycombe Royal Grammar School (U.K.) from 1951 to 1958 and received his BA i ...
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 digital computers. The numerical values tha ...
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 JOIN,
NATURAL JOIN, set differences, and set intersections.
* 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 ...
.
* Support for alterations of
schema definitions via
ALTER and
DROP.
* Bindings for
C,
Ada
Ada may refer to:
Places
Africa
* Ada Foah, a town in Ghana
* Ada (Ghana parliament constituency)
* Ada, Osun, a town in Nigeria
Asia
* Ada, Urmia, a village in West Azerbaijan Province, Iran
* Ada, Karaman, a village in Karaman Province, T ...
, 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 Gene ...
.
* 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 SQL/CLI, or ''Call-Level Interface'', is an extension to the SQL standard is defined in SQL:1999 (based on CLI-95), but also available in later editions such as ISO/IEC 9075-3:2003. This extension defines common interfacing components (struc ...
(
Call Level Interface
The Call Level Interface (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 Standardizati ...
) in 1995
*
SQL/PSM (
stored procedure
A stored procedure (also termed 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 data d ...
s) in 1996
References
External links
The SQL-92 standard
{{SQL
*
Declarative programming languages
Programming languages created in 1992