Friday, February 8, 2019

what are ddl, dml & dcl

what are ddl, dml & dcl


Data Definition Language(DDL) are statements used for defining the database structure or schema.

CREATE statement- to create objects in the database
ALTER statement- to alter the objects in the database
DROP – to delete the objects in the database

Data Manipulation language(DML) are statements used for managing data within schema objects.

SELECT statement- to retrieve data from the a database
INSERT statement- to insert data into a table
UPDATE – to updates existing data

Data Control Language(DCL) are statements used for controling the access of data.

GRANT statement- to give access privileges to database
REVOKE statement- to withdraw access privileges

Conclusion:

DDL statements are auto-commit. That means you cant roll back them.
while DML are not auto-commit. That means you can roll-back the operations

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