Question

I got this two tables:

   CREATE TABLE `reservation` (
   `id_reservation` int(11) PRIMARY KEY,
   `reserved_date` date NOT NULL,
   `id_event` int(11) NOT NULL,   
   FOREIGN KEY (`id_event`) REFERENCES `event` 
   )

   CREATE TABLE `event` (
   `id_event` int(11) PRIMARY KEY,
   `begin_date` date NOT NULL,
   `end_date` date NOT NULL,   
   )

Basically I insert a reservation that has a single reserved_date. The reservation is related to the event, that has a begin_date and an end_date.

I need to check that reserved_date is included (y <= x <= z) in the begin_date and end_date of that particular event.

Answer 1

Try this trigger –

CREATE TRIGGER trigger1
  BEFORE INSERT
  ON reservation
  FOR EACH ROW
BEGIN
  DECLARE id_event_var INT DEFAULT NULL;
  SELECT id_event INTO id_event_var FROM `event` WHERE id_event = new.id_event AND new.reserved_date >= begin_date AND new.reserved_date <= end_date;
  IF id_event_var IS NULL THEN
    ... -- wrong date!
  END IF;
END