Now that PostgreSQL has implemented ALTER TABLE ADD CONSTRAINT etc we should pick a point in time in which we chose to upgrade the toolkit to make proper use of the ON DELETE CASCADE constraint modifier.
Life would be so much easier ... unfortunately Oracle doesn't support the full set (ON DELETE SET NULL or ON DELETE SET DEFAULT or to some value) so we can't manage referential integrity fully in the way SQL expects oen to, but ON DELETE CASCADE's a good first step IMO.