Cheatsheet Pages / SQL Cheatsheet
How SQL transactions work — BEGIN / COMMIT / ROLLBACK
Several changes belong together: either all of them land, or none of them does.
Every example runs against the cheatsheet's sample tables — departments(id, name), employees(id, name, dept_id, salary, manager_id, hired_on) and orders(id, emp_id, amount, ordered_on) — and was executed and verified against SQLite, so you can paste it in and get the same result.
BEGIN;
UPDATE employees SET dept_id = 2 WHERE name = 'Frank';
COMMIT;
-- Frank moves from HR to Sales. If any step fails, ROLLBACK undoes everything as if it never happened
-- Money transfers and stock deductions must run inside a transaction. In MySQL, START TRANSACTION is the same as BEGIN