The most important aspect of a database is the ability to store data and the ability to manipulate data. COMMIT and ROLLBACK are two such keywords which are used in order store and revert the process of data storage. These keywords are usually used in context with a transaction. Let’s try to understand the details about COMMIT and ROLLBACK.
COMMIT and ROLLBACK are performed on transactions. A transaction is the smallest unit of work that is performed against a database. Its a sequence of instructions in a logical order. A transaction can be performed manually by a programmer or it can be triggered using an automated program.
COMMIT is the SQL command that is used for storing changes performed by a transaction. When a COMMIT command is issued it saves all the changes since last COMMIT or ROLLBACK.
Let us consider the following table for understanding Commit in a better way. Customer:-
CUSTOMER ID | CUSTOMER NAME | STATE | COUNTRY |
---|---|---|---|
1 | Akash | Delhi | India |
2 | Amit | Hyderabad | India |
3 | Jason | California | USA |
4 | John | Texas | USA |
Now let us delete one row from the above table where State is “Texas”.
DELETE from Customer where State = 'Texas';
Post the DELETE command if we will not publish COMMIT, and if the session is closed then the change that is made due to the DELETE command will be lost. Updated Command with COMMIT
DELETE from Customer where State = 'Texas';
COMMIT;
Using the above-mentioned command sequence will ensure that the change post DELETE command will be saved successfully.
CUSTOMER ID | CUSTOMER NAME | STATE | COUNTRY |
---|---|---|---|
1 | Akash | Delhi | India |
2 | Amit | Hyderabad | India |
3 | Jason | California | USA |
ROLLBACK is the SQL command that is used for reverting changes performed by a transaction. When a ROLLBACK command is issued it reverts all the changes since last COMMIT or ROLLBACK.
Let us consider the following table for understanding Rollback in a better way. Customer:-
CUSTOMER ID | CUSTOMER NAME | STATE | COUNTRY |
---|---|---|---|
1 | Akash | Delhi | India |
2 | Amit | Hyderabad | India |
3 | Jason | California | USA |
4 | John | Texas | USA |
Now let us delete one row from the above table where State is “Texas”.
DELETE from Customer where State = 'Texas';
Post the DELETE command if we publish ROLLBACK it will revert the change that is performed due to the delete command. Updated Command with ROLLBACK
DELETE from Customer where State = 'Texas';
ROLLBACK;
Using the above-mentioned command sequence will ensure that the change post DELETE command will be reverted successfully.
CUSTOMER ID | CUSTOMER NAME | STATE | COUNTRY |
---|---|---|---|
1 | Akash | Delhi | India |
2 | Amit | Hyderabad | India |
3 | Jason | California | USA |
4 | John | Texas | USA |
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Very well explained! You really make it easy for me🥰
- Irsa
Post the DELETE command if we will not publish COMMIT, and if the session is closed then the change that is made due to the DELETE command will be lost. Updated Command with COMMIT DELETE from Customer where State = ‘Texas’; COMMIT; SQL transaction commit SQL Commit Execution Using the above-mentioned command sequence will ensure that the change post DELETE command will be saved successfully. Output After Commit CUSTOMER ID CUSTOMER NAME STATE COUNTRY 1 Akash Delhi India 2 Amit Hyderabad India 3 Jason California USA SQL Commit example Table After SQL Commit SQL RollBack ROLLBACK is the SQL command that is used for reverting changes performed by a transaction. When a ROLLBACK command is issued it reverts all the changes since last COMMIT or ROLLBACK. Syntax for SQL Rollback ROLLBACK; The syntax for rollback includes just one keyword ROLLBACK. SQL Rollback Example Let us consider the following table for understanding Rollback in a better way. Customer:- CUSTOMER ID CUSTOMER NAME STATE COUNTRY 1 Akash Delhi India 2 Amit Hyderabad India 3 Jason California USA 4 John Texas USA Now let us delete one row from the above table where State is “Texas”. DELETE from Customer where State = ‘Texas’; SQL Delete without rollback SQL Delete without Rollback Post the DELETE command if we publish ROLLBACK it will revert the change that is performed due to the delete command. Updated Command with ROLLBACK DELETE from Customer where State = ‘Texas’; ROLLBACK; SQL rollback example SQL Delete with Rollback Using the above-mentioned command sequence will ensure that the change post DELETE command will be reverted successfully. Output After Rollback CUSTOMER ID CUSTOMER NAME STATE COUNTRY 1 Akash Delhi India 2 Amit Hyderabad India 3 Jason California USA 4 John Texas USA sql rollback command Table after executing Rollback
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