COMMIT, ROLLBACK and SAVEPOINT

Transaction Control Commands

Using SAVEPOINT

START TRANSACTION;
UPDATE students SET marks = 90 WHERE roll_no = 1;
SAVEPOINT sp1;
UPDATE students SET marks = 0 WHERE roll_no = 2;  -- mistake!
ROLLBACK TO sp1;   -- undo only the second update
COMMIT;            -- keep the first update

Summary

• COMMIT saves; ROLLBACK undoes; SAVEPOINT marks a partial undo point.
• ROLLBACK TO savepoint undoes only changes after that point.

Transaction Control Commands

SAVEPOINT का Use

START TRANSACTION;
UPDATE students SET marks = 90 WHERE roll_no = 1;
SAVEPOINT sp1;
UPDATE students SET marks = 0 WHERE roll_no = 2;  -- गलती!
ROLLBACK TO sp1;   -- सिर्फ दूसरा update undo
COMMIT;            -- पहला update रखें

सारांश

• COMMIT save; ROLLBACK undo; SAVEPOINT आंशिक undo point।
• ROLLBACK TO savepoint सिर्फ उस point के बाद के changes undo करता है।