[Solved] Consider this trigger code snippet intended to prevent deletion of rows from Users table if the user is an admin:... What is the main issue if this trigger does not prevent admin deletions? | SQL

SQL - Triggers

Consider this trigger code snippet intended to prevent deletion of rows from Users table if the user is an admin:

CREATE TRIGGER prevent_admin_delete BEFORE DELETE ON Users
FOR EACH ROW
BEGIN
  IF OLD.role = 'admin' THEN
    SIGNAL SQLSTATE '45000' MESSAGE_TEXT = 'Cannot delete admin user';
  END IF;
END;

What is the main issue if this trigger does not prevent admin deletions?

AThe SIGNAL statement syntax is incorrect

BThe condition should check NEW.role instead of OLD.role

CThe trigger does not specify FOR EACH ROW

DThe trigger should be AFTER DELETE, not BEFORE DELETE

Step-by-Step Solution

Solution:

Step 1: Check trigger timing and row context
BEFORE DELETE and FOR EACH ROW are correctly used to check OLD.role before deletion.
Step 2: Verify SIGNAL syntax
In standard SQL, SIGNAL syntax requires correct SQLSTATE and message format. If syntax is wrong, error won't raise and deletion proceeds.
Final Answer:
The SIGNAL statement syntax is incorrect -> Option A
Quick Check:
SIGNAL syntax error prevents trigger from blocking delete [OK]

Quick Trick: Check SIGNAL syntax carefully to block deletes [OK]

Common Mistakes:

Using AFTER DELETE instead of BEFORE DELETE
Checking NEW instead of OLD in DELETE triggers
Omitting FOR EACH ROW clause

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Consider this trigger code snippet intended to prevent deletion of rows from Users table if the user is an admin:

Step 1: Check trigger timing and row context

Step 2: Verify SIGNAL syntax

Final Answer:

Quick Check:

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