Transaction Control Language

1. TRANSACTION CONTROL LANGUAGE (TCL)

2. Learning Objectives: Students
will be able to:
• To understand and use TCL
commands (COMMIT, ROLLBACK,
SAVEPOINT) to control database
transactions.
• To learn how VIEW and SYNONYM
are created and used to simplify
queries and manage data access.
• To understand the role of INDEX in
improving the performance of SQL
queries.
DBMS LAB

3. 1. TRANSACTION CONTROL
LANGUAGE (TCL)
• TCL commands manage
database transactions.
• A transaction is a group of
SQL statements treated as
one unit of work.
• TCL helps save changes
permanently or undo
changes to maintain data
consistency.
DBMS LAB

4. TRANSACTION CONTROL LANGUAGE (TCL) :
DBMS LAB

5. DBMS LAB
Types of TRANSACTION CONTROL
LANGUAGE (TCL) :

6. • The COMMIT command
permanently saves all changes
made during the current
transaction to the database.
Syntax:
COMMIT;
Example:
INSERT INTO Student VALUES (101,
'Amit', 85);
COMMIT;
DBMS LAB
COMMIT

7. ROLLBACK
The ROLLBACK command is used
to undo changes made in the
current transaction since the last
COMMIT or ROLLBACK.
Syntax:
ROLLBACK;
Example:
DELETE FROM Student WHERE
RollNo = 101;
ROLLBACK;
DBMS LAB

8. SAVEPOINT
DBMS LAB
SAVEPOINT is used to set a point
within a transaction to which a
rollback can be performed.
Syntax:
SAVEPOINT savepoint_name;
Example:
SAVEPOINT sp1;
UPDATE Student SET Marks = 90
WHERE RollNo = 102;
ROLLBACK TO sp1;

9. Database Object:
Database Objects in SQL are
logical structures created in a
database to store, manage, and
access data efficiently.
DBMS LAB

10. Database Object:
DBMS LAB

11. • A View is a virtual table based
on the result of a SELECT query.
It does not store data
physically but displays data
from one or more tables.
Syntax:
CREATE VIEW view_name AS
SELECT column1, column2
FROM table_name
WHERE condition;
View:
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12. Example:
CREATE VIEW Student_View AS
SELECT RollNo, Name
FROM Student
WHERE Marks > 60;
SELECT * FROM view_name;
Example:
DROP VIEW Student_View;
View:
DBMS LAB

13. • A Synonym is an alternative
name for a database object
such as a table, view,
sequence, or procedure. It
simplifies object access and
improves security.
Syntax:
CREATE SYNONYM
synonym_name
FOR object_name;
Example:
CREATE SYNONYM stud FOR
Student;
SYNONYMS:
DBMS LAB

14. • An Index is a database object
used to improve the speed of
data retrieval operations on a
table. Indexes are created on
columns frequently used in
search conditions.
Syntax:
CREATE INDEX index_name
ON table_name(column_name);
Example:
CREATE INDEX idx_rollno
ON Student(RollNo);
INDEXES
DBMS LAB

15. • TCL manages database
transactions and ensures data
consistency by allowing users to
save or undo changes.
• Database Objects are logical
structures in SQL used to store,
manage, and retrieve data
efficiently.
• Views, Synonyms, and Indexes
are types of database objects
used to simplify data access,
improve security, and enhance
query performance.
Summary:
DBMS LAB

16. LET’S BEGIN…