Core Data Cascade delete rule sometimes doesn't

• Doug Knowles Core Data Cascade delete rule sometimes doesn't Feb 11 2008, 05:21
  I have an "item" entity in a core data application with a to-many
  relationship to a second entity; the relationship's delete rule is set to
  "cascade", and the inverse (to-one) relationship's delete rule is set to
  nullify.
  I implemented a simple action in my application to delete a selected item,
  which invokes a "delete" method on item to do some cleanup before ultimately
  invoking deleteObject:self on the managed object context.  Everything works
  as expected; deleting the item causes the relationship's target objects to
  be deleted.
  
  I have just implemented an AppleScript command to delete an item, which
  invokes the same "delete" method on item.  However, when the operation is
  completes, the destination objects are not deleted (although the references
  in both directions are cleared).  This leaves my store in an invalid state
  because the target objects are not deleted and have no value for the inverse
  relationship back the item, which is not optional.
  
  I can't figure out any reason why this should behave differently in the two
  different circumstances.  No exceptions are being thrown, and I've stepped
  through the AppleScript deletion and it appears to complete normally.
  
  I have seen this problem in other contexts and coded around it (by deleting
  the target objects explicitly) under the assumption that I was doing
  something wrong.  This is the first case I've encountered where the same
  method works in one situation and fails in another.
  
  Any ideas?
  
  TIA,
  Doug K;
  
  P.S. I've considered filing a bug report, but I can't isolate this code, and
  I know the cascade rule works most of the time, so coding a simple test case
  will in all likelihood not expose the apparent bug.
• Adam Swift Re: Core Data Cascade delete rule sometimes doesn't Feb 11 2008, 20:19
  On Feb 10, 2008, at 8:21 PM, Doug Knowles wrote:
  
  

  > I have an "item" entity in a core data application with a to-many
  > relationship to a second entity; the relationship's delete rule is
  > set to
  > "cascade", and the inverse (to-one) relationship's delete rule is
  > set to
  > nullify.
  > I implemented a simple action in my application to delete a selected
  > item,
  > which invokes a "delete" method on item to do some cleanup before
  > ultimately
  > invoking deleteObject:self on the managed object context.
  > Everything works
  > as expected; deleting the item causes the relationship's target
  > objects to
  > be deleted.
  >
  > I have just implemented an AppleScript command to delete an item,
  > which
  > invokes the same "delete" method on item.  However, when the
  > operation is
  > completes, the destination objects are not deleted (although the
  > references
  > in both directions are cleared).  This leaves my store in an invalid
  > state
  > because the target objects are not deleted and have no value for the
  > inverse
  > relationship back the item, which is not optional.
  >
  > I can't figure out any reason why this should behave differently in
  > the two
  > different circumstances.  No exceptions are being thrown, and I've
  > stepped
  > through the AppleScript deletion and it appears to complete normally.
  >
  > I have seen this problem in other contexts and coded around it (by
  > deleting
  > the target objects explicitly) under the assumption that I was doing
  > something wrong.  This is the first case I've encountered where the
  > same
  > method works in one situation and fails in another.
  >
  > Any ideas?
  >
  

  Have you tried manually calling "processPendingChanges" after the
  delete?  Cascade deletes are not processed immediately:
  
  http://developer.apple.com/releasenotes/Cocoa/CoreDataReleaseNotes/index.ht
  ml
  
  

  > TIA,
  > Doug K;
  >
  > P.S. I've considered filing a bug report, but I can't isolate this
  > code, and
  > I know the cascade rule works most of the time, so coding a simple
  > test case
  > will in all likelihood not expose the apparent bug.
  
• Doug Knowles Re: Core Data Cascade delete rule sometimes doesn't Feb 11 2008, 22:27
  Well, per the tech note, I do call processPendingChanges before I do the
  manual validation (which catches undeleted now-invalid objects).  And my
  understanding is that processPendingChanges is automatically called on a
  Save, which is where I first encountered the invalid records.
  The release note implies that Core Data is doing some work (like propagating
  deletions) at the top of the event loop; could it be that the processing of
  incoming AppleEvents is short-circuiting whatever Core Data normally does?
  
  On Feb 11, 2008 2:19 PM, Adam Swift <aswift...> wrote:
  
  

  > Have you tried manually calling "processPendingChanges" after the
  > delete?  Cascade deletes are not processed immediately:
  >
  >
  > http://developer.apple.com/releasenotes/Cocoa/CoreDataReleaseNotes/index.ht
  ml
  >
  >