Commented by: @livius2

Both cases should raise an error but not your definded exception.
Bug here is that Firebird do not raise exception that "NEW" variables are not avaiable in after delete trigger at all.
In after delete trigger only OLD variables are avaiable.
Of course you can check if it is insertion or deletion inside trigger code.

Commented by: @dyemanov

Karol, IIRC it's documented that unavailable context in universal triggers is returned as NULL.

Commented by: @mrotteveel

@dmitry The documentation says: "In DELETE triggers, references to the NEW variables are invalid and will throw an exception" (see https://www.firebirdsql.org/file/documentation/reference_manuals/fblangref25-en/html/fblangref25-psql-triggers.html#fblangref25-psql-oldnew). I haven't found references for UPDATE OR DELETE triggers.

Commented by: @dyemanov

That is for simple triggers. However, see README.universal_triggers:

3\. In multiple\-action triggers both OLD and NEW contexts are available\. If the
   trigger invocation forbids one of them \(e\.g\. OLD context for INSERT operation\),
   then all fields of that context will evaluate to NULL\. If you assign to
   improper context, runtime exception will be thrown\.

Commented by: @ilya071294

I have prepared a PR:
#225

Commented by: Sean Leyne (seanleyne)

Can we have details on the new functionality?