22
Transactions
•Enroll “Mary Johnson”
in “CSE444”:
BEGIN TRANSACTION;
INSERT INTO Takes
SELECT Students.SSN, Courses.CID
FROM Students, Courses
WHERE Students.name = ‘Mary Johnson’
and
Courses.name =
‘CSE444’
-- More updates
here....
IF
everything-went-OK
THEN COMMIT;
THEN COMMIT;
ELSE ROLLBACK
If system
crashes, the transaction is still either committed or aborted