Guided Notes
Transactions
BEGIN, COMMIT, ROLLBACK, and keeping data consistent with ACID.
All or nothing
Slide 1 / 5A transaction groups several changes into one all-or-nothing unit.
Transferring 100 from Ada to Grace takes two updates: subtract from Ada, add to Grace. If the system crashed between them, 100 would simply vanish.
Inside a transaction, both updates happen or neither does — the database is never left half-updated.