Which code can you use to ensure that the salary is not increased by more than 10% at a time nor is it ever decreased?

technology databases

  1. ALTER TABLE emp ADD CONSTRAINT ck_sal CHECK (sal BETWEEN sal AND sal*1.1);

  2. CREATE OR REPLACE TRIGGER check_sal BEFORE UPDATE OF sal ON emp - 6 - FOR EACH ROW WHEN (new.sal < old.sal OR new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, ‘Do not decrease salary not increase by more than 10%’); END;

  3. CREATE OR REPLACE TRIGGER check_sal BEFORE UPDATE OF sal ON emp WHEN (new.sal < old.sal OR new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, ‘Do not decrease salary not increase by more than 10%’); END;

  4. CREATE OR REPLACE TRIGGER check_sal AFTER UPDATE OR sal ON emp WHEN (new.sal < old.sal OR -new.sal > old.sal * 1.1) BEGIN RAISE_APPLICATION_ERROR ( - 20508, ‘Do not decrease salary not increase by more than 10%’); END;

Show answer
Correct Option: B
Explanation:

To answer this question, the user needs to know about SQL triggers and how they can be used to enforce constraints on database operations. Option B is the correct answer because it creates a trigger that runs before each update of the sal (salary) column in the emp table. The trigger checks if the new salary is less than the old salary or greater than the old salary multiplied by 1.1 (i.e., increased by more than 10%). If either of these conditions is true, the trigger raises an error to prevent the update from occurring.

Option A is incorrect because it uses a check constraint to limit the salary increase, but it does not prevent salary decreases.

Option C is almost correct, but it has a syntax error. The FOR EACH ROW clause is not needed in this case, and the semicolon at the end of the RAISE_APPLICATION_ERROR function call is missing.

Option D is also incorrect because it creates a trigger that runs after each update of the sal column, which means the constraint is not enforced until after the update has already occurred.

Therefore, the correct answer is:

The Answer is: B. CREATE OR REPLACE TRIGGER check_sal BEFORE UPDATE OF sal ON emp

  • FOR EACH ROW WHEN (new.sal < old.sal OR new.sal > old.sal * 1.1)
  • BEGIN
  • RAISE_APPLICATION_ERROR ( - 20508, ‘Do not decrease salary not increase by more than 10%’);
  • END;

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