Summary - Transaction
- SQL course
- Intermediate
- Lesson 105/115
- 5 min
Write a money transfer with BEGIN, COMMIT and ROLLBACK.
Summary - Transaction
A transaction starts with BEGIN, commits with COMMIT or rolls back with ROLLBACK. It provides ACID properties.
BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
COMMIT;Summary transfer.
Practice Summary - Transaction
Summary: write a money transfer transaction (BEGIN, two UPDATEs, COMMIT).
Starter code
-- write summarySample solution
BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
COMMIT;Expected output
Transaction tamamlandı
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What do you do on error?
- SAVEPOINT
- COMMIT
- BEGIN
- ROLLBACK Correct answer
Explanation: On error you ROLLBACK.
2 Summary - Transaction: match the terms
| Term | Meaning |
|---|---|
BEGIN |
start |
COMMIT |
commit |
ROLLBACK |
undo |
ACID |
reliable |