I have just redesigned my core data file to make use of relationships and am having trouble getting by head around how i do things with this new model.

I have an entity called data store that had a one-to-one relationship with a second entity called test (test has a many to one relationship with datastore). I am trying to figure out how to store what record in the test entity has been selected. From what i have found from my goggling i should write 
`[test addDrivingConditionsObject:datastore]` 
Is this how i should be doing it or is there a way to say 
`[datastore addTestObject:test]` which i would prefer.
Thanks