SQL Jobs

SQL is a special-purpose programming language designed for managing data held in a relational database management systems. Originally based upon relational algebra and tuple relational calculus, SQL consists of a data definition language and a data manipulation language. 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. SQL was one of the first commercial languages for Edgar F. Codd's relational model, as described in his influential 1970 paper "A Relational Model of Data for Large Shared Data Banks". Despite not adhering to the relational model as described by Codd, it became the most widely used database language. SQL became a standard of the American National Standards Institute in 1986, and of the International Organization for Standards in 1987. Since then, the standard has been enhanced several times with added features. But code is not completely portable among different database systems, which can lead to vendor lock-in. The different makers do not perfectly follow the standard, they add extensions, and the standard is sometimes ambiguous.