ALT SQL LANGUAGE - REFERENCE GUIDE INTRODUCTION SQL is a relational data language that provides a unified set of facilities for query, data manipulation, data definition, and data control. SQL is both a terminal interface for nonspecialists in data processing, and a data sublanguage embedded in host programming language for use by application programmers. SQL was developed by IBM as the main external interface to be supported by System R, IBM's experimental relational database management system. In 1976, a complete BNF syntax for SQL was published in the "IBM Journal of Research and Development." In 1977, RSI began the development of ORACLE incorporating the SQL language. ORACLE is based on the relational model of data. SQL is a non-procedural language that operates on normalized data. The advantages of the relational model with a non-procedural language are ease of use, maximum data independence, and flexibility.