Data Definition Language (DDL) commands

Data Definition Language (DDL) statements are used to define the database structure or schema.

Some examples:

* CREATE - to create objects in the database
* ALTER - alters the structure of the database
* DROP - delete objects from the database
* TRUNCATE - remove all records from a table, including all spaces allocated for the records are removed
* COMMENT - add comments to the data dictionary
* RENAME - rename an object