Atomicity

#database #computerscience #beginners #sql

Atomicity means a transaction is treated as one complete action, not separate steps. All the operations inside it must succeed together, or else none of them are applied. If something goes wrong in between, the system cancels everything and returns to the original state so no partial changes remain.

Atomicity is what makes a wallet system reliable for me. I see every transfer as one complete action, not separate steps. Either the full transaction happens or nothing happens at all. If something fails in between, everything is cancelled, so no money is lost and no partial updates occurs.

BEGIN;
initiatiing a transaction by detucting money from Alice
UPDATE accounts 
SET balance = balance - 200 
WHERE name = 'Alice';

making a error intentionlly 
UPDATE accounts 
SET balance = balance + 200 
WHERE name = 'Charlie';  (user Charlie does not exist)

COMMIT;