DML statement cannot operate on Trigger.new or Trigger.old

Question

I have an afterInsert trigger on Events. When the Script is finished, I would like to delete the event. I keep getting this error message.

DML statement cannot operate on Trigger.new or Trigger.old

If I cannot do this within Trigger.new, what is the best way to do this? If SOQL is involved, what field am I looking for? event.ID?

Answer 1

You cannot operate on records from the trigger context. You can take those same records and perform DML on them if you simply change the reference.

List<Event> nonTriggerEvents = new List<Event>();
for (Event triggerEvent : trigger.new)
{
    nonTriggerEvents.add(new Event(Id = triggerEvent.Id));
}
update nonTriggerEvents;

However, in this case you can take a simpler approach and call Database.delete on a List<Id>.

List<Id> eventIdsToDelete = new List<Id>();
for (Event newEvent : trigger.new)
{
    eventIdsToDelete.add(newEvent.Id);
}
Database.delete(eventIdsToDelete);