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Core Data Relationship Fault
原标题:

Tracking a familial relationship in Core Data (1 parent entity + 2 types of children, one of which is recursive), trying to create a drop-menu in Interface Builder that lists the names of the parent entities so that the user can choose one to associate as the parent of the entry being edited. I ve got the bindings all set, but when it runs it produces the following error text in the first slot of the menu:

Relationship fault for (<NSRelationshipDescription: 0x100143ed0>), name parent, isOptional 1, isTransient 0, entity Family, renamingIdentifier parent, validation predicates ( ), warnings ( ), versionHashModifier (null), destination entity Family, inverseRelationship subFamilies, minCount 0, maxCount 0 on 0x10025c850

I ve done a little bit of reading around online, and it appears to have to do with the fact that I ve got a many-to-one relationship set up (as one parent can have multiple children, but I want to limit each child to only one parent). I ve been trying to figure out a way to restructure the data model to not put a many-to-one relationship on something that ll need to be called up in such a fashion, but I m getting stuck trying to figure out how to track the children. Any ideas on possible methods of resolving the issue?

最佳回答

A fault in Core Data is not an error, it just means that the what you are trying to access hasn t been retrieved from the database yet. If you do something like [fetchResults valueForKey:@"name"] it will fire and you should get what you expect. It shouldn t be a problem with your relationship model.

By the way, "minCount 0, maxCount 0" seems weird. Is that really what you want? minCount of 0 and maxCount of 1 should make more sense.

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