Definition of SQL
SQL is the acronym for Structured Query Language. It is a special purpose computer programming language, which has been designed for the purpose of data management that is kept in a Relational Database Management System (RDBMS), or for the processing of stream data in a Relational Data Stream Management System (RDSMS).
The SQL programming language was originally developed on the basis of tuple relational calculus and relational algebra. The major components of this language include the following:
- Data definition language
- Data manipulation language
- Data Control Language.
The areas within which SQL programming language can be used include data insertion, update, query, and delete, data access control, and modification and creation of schema. Even though SQL programming language is regarded as a declarative language to a great extent, but it also consists of some procedural elements.
History of SQL
Raymond F. Boyce and Donald D. Chamberlin started the initial development of SQL at IBM in the beginning of the 1970s. The early version of the language, which was referred to as SEQUEL (short form for Structured English Query Language), was developed for the purpose of manipulating and retrieving the data that was stored on System R, which was quasi-relational and original database management system of IBM.
This system was developed by a group of individuals at San Jose Research Laboratory of IBM during the era of 1970s. The name of this version was later changed from SEQUEL to SQL. This is because the name “SEQUEL” was already trademarked by Hawker Siddeley, which was an aircraft company based in the United Kingdom.
Relational Software, Inc., which is now famous as Oracle Corporation, realized the abilities of the concepts and ideas presented by Boyce, and Codd, Chamberlin. As a result, the company began working on the development of its own RDBMS, which was based on SQL, at the end of 1970s.
The company had an aim of selling this system to the Central Intelligence Agency, U.S. Navy, and other prominent agencies of U.S. government. The first implementation of SQL, which was available commercially, was released by Relational Software, Inc. in June 1979. It was named Oracle Version 2 (V2) and it operate on VAX computers.
IBM conducted various tests of SQL at customer sites so as to identify the degree of practicality and usefulness of this system. The company that started developing products, such as SQL/DS, DB2, and System/38, for commercial purposes. These products were based on the prototype of system R.