Final answer:
The ROLLBACK command is used to undo changes in a database before they are committed. It reverses all changes made to the database during the current transaction.
Step-by-step explanation:
The command used to undo changes that have not yet been committed in many database management systems is ROLLBACK. This SQL command is essential for managing transactions in databases. When you issue a ROLLBACK command, the database system will undo any changes made during the current transaction, reverting tables or records to their previous state. This capability is crucial for maintaining data integrity, especially in systems where many users are interacting with the data simultaneously.
Example of ROLLBACK Use
If you are in a transaction and execute several insert, update, or delete operations, and you realize that you made a mistake or need to cancel the operations, you simply execute the ROLLBACK; the database will undo all changes made since the start of the transaction.