Preventing users from inserting rows without an id.

Problem

Create a trigger that will prevent a user from inserting a row into a table if the user's id is not in the table.
Input:
INSERT INTO table1 (id, name) VALUES (1, 'John')
Output:
ERROR: The user's id is not in the table.

Solution

This solution is in SQL. Our A.I. can create solutions in multiple languages.

sarastevens

CREATE TRIGGER check_user_id
BEFORE INSERT ON table1
FOR EACH ROW
BEGIN
  IF NOT EXISTS (SELECT id FROM table1 WHERE id = NEW.id) THEN
    SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'The user''s id is not in the table.';
  END IF;
END;

/*

The trigger is optimal because it is a BEFORE INSERT trigger, which means that it will be executed before the row is inserted into the table.

*/