Question

I want to make a trigger that will prevent the insertion if the birthdate (one of the columns) is in the future. I have this:

CREATE TRIGGER foo
BEFORE INSERT ON table
FOR EACH ROW
BEGIN
  IF NEW.birthdate > CURRENT_DATE()
  THEN
    //How do I prevent the insert right here???
  END IF;
END;

How can I cancel the insert inside the if statement?

Answer 1

Based on this I’m not sure if it’s possible to do it that way.

There’s no support in MySQL’s current
implementation of triggers to
voluntarily throw an exception and
abort the statement that spawned the
trigger.

The workaround I’ve found is to write
a BEFORE trigger to set one of the
not-NULL columns in the table to NULL,
thus violating its NOT NULL
constraint. This causes the statement
that spawned the trigger to be
aborted.