SQL DML and DDL

     SQL can be divided into two parts:

(1)     The Data Manipulation Language (DML)

(2)     The Data Definition Language (DDL).

         The Data Manipulation Language (DML) :  The query and update    commands   form the DML part of SQL. Following are important DML statements.

• SELECT – Select statement is used to extracts data from a database
• UPDATE -  Upadte statement is used to  updates data in a database
• DELETE -  Delete statement is used to deletes data from a database
• INSERT INTO –Insert Into statement is used to inserts new data in a database

    The Data Defination Language (DDL) : The DDL part of SQL permits database tables to be created or deleted. It also define indexes (keys), specify links between tables, and impose constraints between tables. The most important DDL statements in SQL are:

• CREATE DATABASE -  is used to creates a new database
• ALTER DATABASE - is used to  modifies a database
• CREATE TABLE - is used to  creates a new table
• ALTER TABLE - is used to modifies a table
• DROP TABLE - is used to deletes a table
• CREATE INDEX - is used to creates an index (search key)
• DROP INDEX - is used to deletes an index