SQL, DDL, DML, DCL and TCL Terms – What on earth are those?

11/16/2009 4:55:59 AM

Sure you heard those acronyms very often… but do you know what they really mean?

Every DBMS (Database Management System), such as Oracle, Sybase, DB2 and of course SQL Server, have their own command language. This language is the interface that allows you to take actions over a database.

These languages are command based. These commands are divided into the following groups and their syntax and functionality may vary from DBMS to DBMS. These acronyms refer to command groups or category.

SQL (Structure Query Language)

This is the globally accepted name when you refer to a language used as an interface for a DBMS. All commands groups are categorized under SQL. Each command is also known as a “SQL statement”.

DDL (Data Definition Language)

Used to create or remove objects and modify their structure in a database.

Commands: CREATE, DROP, ALTER

DML (Data Manipulation Language)

Used to manipulate data in a database. With them, you can retrieve, insert, update and delete records in a specific table.

Commands: SELECT, INSERT, UPDATE, DELETE

DCL (Data Control Language)

Used to administer security permissions on database objects.

Commands: GRANT, REVOKE

TCL (Transactional Control Language)

Used to manage transactions in a database.

Commands: TRANSACTION, COMMIT, ROLLBACK