DDL - Data Definition Language : allows you to define the structure of the data. This language gives a facility to define the create tables in case RDBMS. All these definitions will be stored in a special table called data dictionary table.
DML - Data Manipulation Language : provides tools that allow modification and retrieval of data.
Data Control Language – DCL : it allows control over user access privileges of data. As result of DCL, user access is restricted and controlled.