Data Definition Language DDL

DDL (data definition Language): Primarily used to manipulate the structure of an Oracle database. Define, modify, and delete objects of each type.

It consists of create, alter, and drop 3 statements.

(1) The CREATE statement is used primarily for creating database objects, such as databases, tables, indexes, subroutines (functions, stored procedures), triggers, views, and so on.

(2) The ALTER statement is used to modify the database object.

--Add columns

ALTER TABLE table1 add column1 varchar2 (+) null;

--Delete Columns

ALTER TABLE table1 drop column column1;

(3) The drop statement is used to remove the database object.

One feature of all DDL statements is that each DDL statement contains an implicitly committed transaction statement , so whenever these commands are executed, the system commits the changes to the database.

Data Definition Language DDL