> Normally I would expect this to trigger the OnError Event of
> the Dataset, or the OnDeleteError. None of them are triggered.

Can you run the app using Debug DCUs and set a breakpoint in
the TDataSet.Delete; method (vcl db.pas unit). Stepping
through the code should take you into TDataSet.CheckOperation
and from there eventually into TIBOUpdateSQL.ExecSQL
which is where (in theory) a EDatabaseError should be raised
and not an EIB_DatabaseError.

It seems likely that you are not getting into
TIBOUpdateSQL.ExecSQL but into some other internal/native
delete method that is raising an EIB_DatabaseError, but it
would be interesting to see where/why - so a callstack from
the place that this error is raised may help.

--
Geoff Worboys
Telesis Computing