how do Delphi events coexist with IB triggers and constraints ?

say I define a BeforeDelete event for table A:

- will Delphi translate it into an IB trigger ?
- if a trigger before delete is defined, which will be called first ?
- the following constraint

add constraint <constraint_name> foreign key (ParentID)
references parent (ParentID)
ON DELETE CASCADE

will call my BeforeDelete code ?

Thank you

Duilio Foschi