ER-Designer supports Triggers. The screen shot on the left of the Entity (Table) editor shows the SQL tab. This is only available in the physical model, as SQL does not exist in the logical space.
The SQL tab shows the automatically generated delete trigger for this table. ER-Designer knows the child tables, and the Foreign Keys in the child tables and they relate to this table. With this information, a delete trigger is generated. And most importantly, your headaches of "dangling data" and an inconsistent database are gone.
In addition to the foreign key derived delete triggers ER-Designer has support for user defined triggers. The screen shot below shows the User constraint editor.