Along with Codd's definition of the relational model, he proposed a language called DSL/Alpha for manipulating the data in relational tables. Shortly after Codd's paper was released, IBM commissioned a group to build a prototype based on the ideas of Codd. This group created a simplified version of DSL/Alpha that they called SQUARE and refinements to SQUARE led to a language called SEQUEL, which was, finally, renamed SQL. SQL is now entering middle age and it has undergone a great deal of change along the way. In the mid-1980s, the American National Standards Institute (ANSI) began working on the first standard for the SQL language, which was published in 1986. Subsequent refinements led to new releases of the SQL standard in 1989, 1992, 1999, 2003, and 2006. Along with refinements to the core language, new features have been added to the SQL language to incorporate object-oriented functionality. The latest standard, SQL:2011, focuses on the integration of SQL and XML and defines a language called XQuery which is used to query data in XML documents.
- SQL 2008 Legalizes ORDER BY outside cursor definitions. Adds INSTEAD OF triggers. Adds the TRUNCATE statement
- SQL:2011 is the seventh revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2011.
SQL goes hand in hand with the relational model because the result of an SQL query is a table or result set. Thus, a new permanent table can be created in a relational database simply by storing the result set of a query. Similarly, a query can use both permanent tables and the result sets from other queries as inputs. When referring to the language, it is equally acceptable to say the letters individually (i.e., S. Q. L.) or to use the word sequel.