SQL (Structured Query Language) is a specialized programming language designed for managing and manipulating data stored in relational databases. It is particularly useful for handling structured data, which involves relations among entities and variables.

Key Principles

SQL was introduced in the 1970s and became one of the first commercial languages to use Edgar F. Codd's relational model. It was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce and was originally called SEQUEL (Structured English Query Language). SQL became a standard of the American National Standards Institute (ANSI) in 1986 and of the International Organization for Standardization (ISO) in 1987.

Components and Capabilities

SQL consists of several types of statements, which can be informally classified into sublanguages:

• Data Query Language (DQL): Used for querying data.

• Data Definition Language (DDL): Used for defining database schemas.

• Data Control Language (DCL): Used for controlling access to data.

• Data Manipulation Language (DML): Used for inserting, updating, and deleting data.