SQL
Structured Query Language

SQL (sometimes pronounced "sequel") is an industry-standard language for creating, updating and, querying relational database management systems. At a basic level it is very simple to learn, but paradoxically, it is extremely powerful and useful.

SQL was developed by IBM in the 1970s for use in System R, an early relational database. It is the de facto standard as well as being an ISO and ANSI standard. It is often embedded in general purpose programming languages.

• DDL (Data Definition Language) statements which allow the programmer to define database structures, e.g.

  create table PEOPLE (
      name varchar2(60),
      age integer
  )

  This simple DDL statement creates a table called PEOPLE with columns to store name and age. The name column can contain alphanumeric characters, upto 60 in length, and the age column can contain integers.
• DML (Data Manipulation Language) statements allow the data in the database to be updated by the user or the application. e.g.

  update PEOPLE set age = 18 where name = "John"
  

  This statement sets John's age to 18 in the PEOPLE table.

See also:
[Database]  [MySQL]  [Oracle]  [Oracle Discoverer]  [RDBMS]