What is sql?

What is sql?

SQL (structured Query Language: Structured Query Language) is a special-purpose programming language used to manage relational database management systems (RDBMS), or in relational stream data management systems (RDSMS) Perform stream processing.

SQL is based on relational algebra and tuple relational calculus, including a data definition language and data manipulation language. The scope of SQL includes data insertion, query, update and deletion, database schema creation and modification, and data access control. Although SQL is often described as, and is largely a declarative programming (4GL), it also contains elements of procedural programming.

SQL is the first commercial language implementation of Edgar Corder's relational model, which was described in his influential 1970 paper "A Model for Large Shared Databases". Relational Model" is described. Although SQL is not designed entirely according to Codd's relational model, it has still become the most widely used database language.

SQL became a standard of the American National Standards Institute (ANSI) in 1986 and an International Organization for Standardization (ISO) standard in 1987. Since then, this standard has gone through a series of revisions, adding a large number of new features. Despite the existence of this standard, most SQL code is not fully cross-platform across different database systems.

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