Structured Query Language (SQL): As the name denotes SQL is the best at writing queries. It is available in a number of database management packages based on the relational model of data. For example, in DB2 of the IBM and UNIFY of the UNIFY corporation.
Originally defined by D.D. Chamberlain in 1974, SQL underwent a number of modifications over the years. Today SQL has become an official ANSI standard. Today SQL is used in database management systems of many platforms.