Structured Query Language (SQL) is a declarative, domain-specific programming language used for relational database management systems (RDBMS). It was first developed by Donald Chamberlin and Raymond Boyce at IBM in the 1970s, with the first commercially available SQL-based RDBMS, Oracle v2, released in 1979. The language allows developers to create database tables, add, edit and delete entries, change the structure of tables, and manage indexes and stored procedures. Its syntax contains several elements, including clauses, expressions, predicates and queries. The proprietary file format is .sql.