History

SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd^[12] in the early 1970s.^[13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM’s original quasirelational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s.^[13]

Chamberlin and Boyce’s first attempt at a relational database language was SQUARE (Specifying Queries in A Relational Environment), but it was difficult to use due to subscript/superscript notation. After moving to the San Jose Research Laboratory in 1973, they began work on a sequel to SQUARE.^[12] The original name SEQUEL, which is widely regarded as a pun on QUEL, the query language of Ingres,^[14] was later changed to SQL (dropping the vowels) because “SEQUEL” was a trademark of the UK-based Hawker Siddeley Dynamics Engineering Limited company.^[15] The label SQL later became the acronym for Structured Query Language.

After testing SQL at customer test sites to determine the usefulness and practicality of the system, IBM began developing commercial products based on their System R prototype, including System/38, SQL/DS, and IBM Db2, which were commercially available in 1979, 1981, and 1983, respectively.^[16]

In the late 1970s, Relational Software, Inc. (now Oracle Corporation) saw the potential of the concepts described by Codd, Chamberlin, and Boyce, and developed their own SQL-based RDBMS with aspirations of selling it to the U.S. Navy, Central Intelligence Agency, and other U.S. government agencies. In June 1979, Relational Software introduced one of the first commercially available implementations of SQL, Oracle V2 (Version2) for VAX computers.

By 1986, ANSI and ISO standard groups officially adopted the standard “Database Language SQL” language definition. New versions of the standard were published in 1989, 1992, 1996, 1999, 2003, 2006, 2008, 2011,^[12] 2016 and most recently, 2023.^[17]