Data sublanguage consists of two parts :
- Data Definition Language : To specify Database Schema.
- Data Manipulation Language : To express database queries and updates.
1.Data Definition Language (DDL):
Database schema is specified by a set of definition which are expressed by a specific language called Data Definition Language (DDL).
Data Dictionary : The result of compilation of DDL statement is a set of tables, which is stored in a special file called data dictionary or system catalogues. This file contain META data i.e. data about data.