SQL Structured Query Language is a special purpose
language designed for managing data held in a relational database
management system (RDBMS), or for stream processing in a relational
data stream management system (RDSMS).
Originally based upon relational
algebra and tuple relational calculus, SQL consists of a data
definition language, data manipulation language, and Data Control
The scope of SQL includes data
insert, query, update and delete , schema creation and modification,
and data access control. Although SQL is often described as, and to a great
extent is, a declarative language , it also includes procedural elements.