chap 5 Query pro

 






DML, DDL, DCL and TCL Statements in SQL with Examples


DML (Data Manipulation Language)

DML statements affect records in a table. These are basic operations we perform on data such as selecting a few records from a table, inserting new records, deleting unnecessary records, and updating/modifying existing records.

DML statements include the following:

SELECT – select records from a table
INSERT – insert new records
UPDATE – update/Modify existing records
DELETE – delete existing records

DDL (Data Definition Language)

DDL statements are used to alter/modify a database or table structure and schema. These statements handle the design and storage of database objects.

CREATE – create a new Table, database, schema
ALTER – alter existing table, column description
DROP – delete existing objects from database

DCL (Data Control Language)

DCL statements control the level of access that users have on database objects.

GRANT – Give access rights to the database 
REVOKE – Remove access rights to the database 



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