BEGIN - MySQL

Overview

The BEGIN command in MySQL initiates a transaction that groups multiple database operations together. It marks the beginning of a transaction block where changes to the database are not committed until an explicit COMMIT is issued. Transactions ensure data integrity and consistency by allowing multiple operations to be treated as a single unit.

Syntax

BEGIN [WORK]

Options/Flags

  • WORK: Optional keyword that can be added after BEGIN. It has no effect on the command’s behavior.

Examples

Simple Transaction:

BEGIN;
UPDATE users SET name = 'John Doe' WHERE id = 1;
COMMIT;

Rollback Transaction:

BEGIN;
UPDATE users SET name = 'Jane Doe' WHERE id = 1;
ROLLBACK;

Common Issues

  • Lost Connection: If the connection is lost before COMMIT, the transaction will automatically rollback.
  • Deadlock: Transactions can deadlock when multiple transactions attempt to modify the same data concurrently.
  • Nested Transactions: MySQL does not support nested transactions.

Integration

BEGIN transactions can be combined with SAVEPOINT to create save points within a transaction. This allows for specific points within the transaction to be rolled back independently.

  • COMMIT: Finalizes and commits changes made within a transaction.
  • ROLLBACK: Cancels a transaction and rolls back changes made within it.
  • SAVEPOINT: Creates a named save point within a transaction.