? COMMIT and ROLLBACK in SQL

These two commands are part of transaction control in SQL, used to manage changes made by a series of SQL statements.

1. COMMIT

• Saves all changes made in the current transaction permanently to the database.

• Once committed, changes cannot be undone by rollback.

• Used to finalize a transaction.

Syntax:

COMMIT;

Example:

BEGIN TRANSACTION;UPDATE accounts SET balance = balance - 100 WHERE account_id = 1;UPDATE accounts SET balance = balance + 100 WHERE account_id = 2;COMMIT;

2. ROLLBACK

• Undoes all changes made in the current transaction.

• Reverts the database to the state before the transaction began.

• Used to cancel or undo changes if an error occurs.

Syntax:

ROLLBACK;

Example:

BEGIN TRANSACTION;UPDATE accounts SET balance = balance - 100 WHERE account_id = 1;-- Suppose something goes wrong hereROLLBACK;

? Key Points

• Transactions group multiple SQL statements into a single unit.

• Use COMMIT to make changes permanent.

• Use ROLLBACK to discard changes on error or unwanted situations.

• Some databases start transactions implicitly; others require explicit BEGIN TRANSACTION.

• Helps maintain data integrity and consistency.

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