SQL, a language for database management

SQL is convenient for managing large collections of data with a predefined list of components. The classical activity of an enterprise, transactions and resources are perfectly managed by a such tool while intelligent information processing requires another format as XML.

This is the most used language for building and using relational databases. The original name was SEQUEL that is a short for "Structured English QUEry Language", but was condensed to SQL and the full name "Structured Query Language", come then. Must be pronounced S-Q-L.
The authors are Donald D. Chamberlin and Raymond F. Boyce at IBM. The System/38 implemention was sold by IBM in 1979, and Oracle by Relational Software in the same year. In 1982 IBM implemented SQL in DB2.
SQL becomes ANSI standard in 1986, ISO standard in 1987 but actual implementations are far to be standardized.
SQL 2003 added XML features to the language.

Variants and procedural extensions

SQL relational model

SQL 2003 features

In the relational model, queries are expressed declaratively as relations between categories of data (and, or, mainly).

Sample code

Hello world. 

CREATE TABLE message (text char(15));


INSERT INTO message (text) VALUES ('Hello, World!');


SELECT text  FROM message;


DROP TABLE message;

Choose articles that cost is less than 50 $. 

SELECT * FROM article  
WHERE price < 50

See also:

Documents and references: