DDL
full spelling ： Data Definition Language
Data Definition Language is a language used by a database management system which allows users to define the database, specifying data types, structures and constraints on the data. It is a computer language for defining data. XML Schema is an example of a DDL.
There are four basic DDL SQL commands Create, Drop, Truncate and Alter. These commands will primarily be used by database administrators during the setup and removal phases of a database.