SQL Data Definition Language (DDL)

The Data Definition Language (DDL) part of SQL permits database tables to be created or deleted. We can also define indexes (keys), specify links between tables, and impose constraints between database tables.

The most important DDL statements in SQL are:

·         CREATE TABLE: create a new database table

·         ALTER TABLE: alters(change ) a database table

·         DROP TABLE: delete a database table

·         CREATE  INDEX: create an index(search key)

·         DROP INDEX: delete an intex