DMZ 1.7.1 (DataMapper OverZealous Edition)

[eluser]OverZealous[/eluser]
kre8ivdesigns
You don't have to go through all of that. DMZ automatically deletes the relationships when you delete the item. Just do $rate->delete() and it will delete the item.

Please read the manual a little more thoroughly before posting. Many of your questions are easily resolved by looking through the manual and the examples included. For example, see the bright yellow section on the Delete page in the manual to see how delete works.