How Transactions Are Controlled
The COMMIT and ROLLBACK statements allow control of the effects of a transaction on the database:
• The COMMIT statement makes the changes permanent.
• The ROLLBACK statement undoes the changes made by the transaction.
When a COMMIT statement is issued, the DBMS makes all changes resulting from the transaction permanent, terminates the transaction, and drops any locks held during the transaction. When a ROLLBACK statement is issued, the DBMS undoes any database changes made by the transaction, terminates the transaction, and releases any locks held during the transaction.