What
are the different types of operation possible in DBMS?
1. DDL (Data Definition Language):
DDL or Data Definition Language actually consists of the SQL commands that can
be used to define the database schema. It simply deals with descriptions of the
database schema and is used to create and modify the structure of database
objects in database.
Examples of DDL commands:
CREATE
– is used to create the
database or its objects (like table, index, function, views, store procedure
and triggers).
DROP – is used to delete objects from the
database.
ALTER-is used to alter the structure of the
database.
TRUNCATE–is used to remove all records from a
table, including all spaces allocated for the records are removed.
COMMENT –is used to add comments to the data
dictionary.
RENAME –is used to rename an object existing in
the database.
2. DML (Data Manipulation Language):
The
SQL commands that deals with the manipulation of data present in database
belong to DML or Data Manipulation Language and this includes most of the SQL
statements.
Examples
of DML:
SELECT – is used to retrieve data from a
database.
INSERT – is used to insert data into a table.
UPDATE – is used to update existing data within
a table.
DELETE
– is used to delete records
from a database table.
3.
DCL
(Data Control Language):
DCL
includes commands such as GRANT and REVOKE which mainly deals with the rights,
permissions and other controls of the database system.
Examples
of DCL commands:
GRANT-gives user’s access privileges to
database.
REVOKE-withdraw user’s access privileges given
by using the GRANT command.
4. TCL (transaction Control Language):
TCL
commands deals with the transaction within the database.
Examples
of TCL commands:
COMMIT– commits a Transaction.
ROLLBACK– rollbacks a transaction in case of any
error occurs.
SAVEPOINT–sets a save point within a transaction.
SET
TRANSACTION–specify
characteristics for the transaction.
