PDOrollBack
PDO rollback refers to a feature within PHP's PDO (PHP Data Objects) extension that allows for the cancellation of pending database transactions. When a transaction is started, subsequent database operations are held in a pending state. A rollback operation discards all of these pending operations and reverts the database to the state it was in before the transaction began. This is crucial for maintaining data integrity, particularly in scenarios where multiple related database modifications must either all succeed or all fail. For example, if a user is making a purchase that involves updating inventory and recording the order, and the inventory update fails, the entire operation should be rolled back to prevent an inconsistent state where an order is recorded but no inventory is deducted. To initiate a rollback, the `rollBack()` method is called on the PDO object. This method should typically be used within an exception handling block or a conditional check that determines if an error has occurred during the transaction. If the transaction completes successfully without any errors, a commit operation, using the `commit()` method, would be used instead to finalize the changes.