title: Understanding Core Data delete rules on One to Many
body: <p>I am a little fuzzy about Core Data Relationships deletion rules. So if someone could help me answer a few questions about them.</p>
  
  <p>I have Entities A and B. A has a to-Many relationship with B, and B has a to-One relationship with A.</p>
  
  <p>A&lt;--->>B</p>
  
  <p>Now, if I set the delete rule at A to Cascade, I understand it will delete all the Bs related to it. But if I set it to Nullify, will it set the Bs to NIL or just the Foreign Key to Nil?</p>
  
  <p>And I looked everywhere about the relationship from B to A, should I set it to Nullify? Will that just Nullate the "B Object" at A? Or will it Nullify all the Bs associated with A? What about Cascade? Will it delete all the Bs associated with A, or just the particular B?</p>
  
  <p>Or do I just use "No Action" on the relation from B to A so that when I delete B, no change will happen to A, but the reference to B won't exist?</p>
  
  <p>I am PRETTY confused with these, so excuse my questions.</p>
  
  <p>Thanks.</p>