Types of DataBase Languages In DBMS.

Data sublanguage consists of two parts :

1. Data Definition Language : To specify Database Schema.
2. 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.

Data Storage and Definition Language : The storage structure and access methods used by the database system are specified by a set of definitions in a special type of DDL called Data Storage and Definition Language.

2.Data Manipulation Language (DML):

DML is a language that enables users to access or manipulate data as organized by the appropriate data model.

Data Manipulation means.

• To RETRIEVE the information from Database.
• To INSERT information into database.
• To DELETE information from Database.
• To MODIFY information from database.

There are two types of DML.

1. Procedural DML : It requires a user to specify what data are needed and how to get those data.

2. Non-Procedural DML : It requires a user to specify what data are needed without specifying how to get those data.

Query is a statement requiring or requesting the retrival of information.

Query language is the portion of DML that involves information retrial.