TCL COMMANDS

 TCL COMMANDS(transaction control language)

It control the transaction of database

It has three commands

commit rollback and savepoint

syntax:

commit;

rollback;

savepoint savepoint name;

 select *from player;

RANK	NAME	SCORE
1	virat	183
2	dhoni	183
3	rohit	264

Update player set name=’kohli’ where rank=1;

1 row updated

select * from player;

RANK	NAME	SCORE
1	kohli	183
2	dhoni	183

 rollback;

rollback completed

select * from player;

 

RANK	NAME	SCORE
1	virat	183
2	dhoni	183

Update player set name=’kohli’ where rank=1;

1 row updated

select * from player;

RANK	NAME	SCORE
1	kohli	183
2	dhoni	183

 rollback;

rollback completed

select * from player;

RANK	NAME	SCORE
1	virat	183
2	dhoni	183

 Delete from player where rank=1;

1 row deleted

select * from player;

RANK	NAME	SCORE
2	dhoni	183

Rollback;

rollback completed

select * from player;

RANK	NAME	SCORE
1	virat	183
2	dhoni	183

 SAVEPOINT

select * from player;

RANK	NAME	SCORE
1	virat	183
2	dhoni	183

Save point A;

Save point created

Insert into player values(3,’dhawan’,143);

1 row created

Insert into player values(4,’sachin’,100);

1 row created

Insert into player values(5,’pandya’,108);

 rollback to B;

rollback complete

select * from player;

RANK	NAME	SCORE
1	virat	183
2	dhoni	183
3	Dhawan	143
4	Sachin	100
5	pandya	108