Databases: SQL

SQL (Eng. Structured Query Language - Structured Query Language) - a universal computer language used to create, modify and manage data in relational databases. Contrary to misconceptions, SQL is an information-logical language, not a programming language. SQL is based on the relational algebra.

In the early 1970s, the company IBM has developed an experimental database «System R» on the basis of the language SEQUEL (Structured English Query Language - Structured English Query Language). Later, for legal reasons the language SEQUEL was renamed from SQL. In 1986, when the first SQL standard was adopted by ANSI (American National Standards Institute), an official pronunciation was [, es kju: 'el] - es-cue-el. Despite this, even the English-speaking specialists still often called SQL sequel, instead of es-cue-el (in Russian often say "es el ku").

The aim of the development was to create a simple non-procedural language that can benefit anyone, even with no programming skills. Actually the development of language query takes Chemberlin (Chamberlin) and Ray Boyce (Ray Boyce). Pat Selinger (Pat Selinger) was developing a cost-based optimizer (cost-based optimizer), Laurie Raymond (Raymond Lorie), the compiler needs.

In 1981, IBM announced its first SQL-based software product - SQL / DS. A little later, it was joined Oracle, Relational Technology and other manufacturers.

The first SQL standard was adopted by ANSI in 1986 and ISO (International Organization for Standardization) in 1987 (the so-called SQL level 1) and later revised in 1989 (SQL level 2). Further development of the language database vendors required the adoption in 1992 of a new extended standard (ANSI SQL-92 or SQL-2 only). The following standards became the SQL-99. Currently a standard adopted in 2003 (SQL-3). SQL rightfully won the championship among the similar query languages.