DDL statements are used to create, delete, or change the objects of a database. Typically a database administrator is responsible for using DDL statements or production databases in a large database system.

CREATE
      The CREATE command can be used to establish each of these databases on the platform.

SQL> create table Employ (name varchar2 (20), eid number (10), salary number (10));

Table created.

ALTER

The ALTER command allows to make changes to the structure of a table without deleting and recreating it.

SQL> alter table Employ add gender varchar2 (20);

Table altered.

DROP
The final command of the Data Definition Language, DROP, allows to remove the entire database objects from the DBMS.

SQL> DROP TABLE personal_info;

Table dropped.