IF EXISTS(SELECT *
          FROM sys.objects
          WHERE [name] = 't_conference_conference_day_connection' AND TYPE = 'TR')
  DROP TRIGGER [dbo].[t_conference_conference_day_connection]
GO

CREATE TRIGGER [dbo].[t_conference_conference_day_connection]
  ON [dbo].[conference_days]
  AFTER INSERT, UPDATE, DELETE
AS
  BEGIN
    IF EXISTS(SELECT *
              FROM inserted AS i LEFT OUTER JOIN conferences AS c ON i.conference_id = c.id
              WHERE c.start_time = NULL)
      THROW 50000, 'Conference id not in database', 1

    IF EXISTS(SELECT *
              FROM inserted AS i INNER JOIN conferences AS c
                  ON c.id = i.conference_id AND i.[day] NOT BETWEEN c.start_time AND c.end_time)
      THROW 50000, 'Conference day not in conference time', 1
    -- TODO
    -- nie działa. cholera wie czemu, przerobiłem to, dalej nie działa, nie mam pomysłu co może kolidować (odpalaj z generatorem).
     IF EXISTS(SELECT *
               FROM inserted AS i INNER JOIN conference_days AS cd
               ON cd.[day] = i.[day]
               AND cd.[conference_id] = i.[conference_id]
               where cd.id <> i.id)
       THROW 50000, 'There is already a conference day in this date', 1
  END