Category: Definition

Structured Query Language, SQL

Structured Query Language or short SQL is a computer language to create, modify and control relational databases. SQL is standardised according to ANSI (American National Standards Institute).

The Language Layers of SQL

SQL can be split into four seperate layers:

Data Definition Language (DDL) - to define a database schema.
Data Query Language (DQL) - to retrive data from a database.
Data Manipulation Language (DML) - for changing or deleting records.
Data Control Language (DCL) - for controlling database resources.