Answer & Explanation

4 Answers
Verified Correct Answer

Option A

ALTER TABLE employees ADD CONSTRAINT fk_employee_manager FOREIGN KEY (manager_id) REFERENCES employees(id) ON DELETE SET NULL;
Additional Explanation
Correct implementation. Prefer parameterized queries in application code, validate affected rows for UPDATE/DELETE, and use transactions for related writes.
Sarkari Resultess
Editorial Answer 1
Verified

Option B

ON DELETE UPDATE;
Additional Explanation
This option is incorrect for the stated requirement.
Sarkari Resultess
Editorial Answer 2
Verified

Option C

ON DELETE REMOVE;
Additional Explanation
This option is incorrect for the stated requirement.
Sarkari Resultess
Editorial Answer 3
Verified

Option D

ON DELETE CASCADE is identical to SET NULL.
Additional Explanation
This option is incorrect for the stated requirement.
Sarkari Resultess
Editorial Answer 4