sql statement error cause cannot fetch data when relationship of relationship is nil in fetch statement

[SimonSuo]

Reproduce steps:
1, create a model, add a relationship to an entity.
2, add a relationship to the entity of #1 destination of relationship.
3, use the FetchRequest in core data to load data, E.G. "[NSPredicate predicateWithFormat:@"user.posts.comments = nil"];" --- the condition is entity.relationship1.relationship2 == nil.
4. check the sql statement generate by EncryptedStore. The record in database is **relationship1.relationship2__objectID is NUL _actually, but the sql statement always show like _relationship1.relationship2__objectID = relationship2.__objectID and relationship2.__objectID is NULL.
Suggestion: maybe need to some special process for the case -- the relationship is NULL. Change to directly relationship1.relationship2__objectId is NULL

[DanielBroad]

Hmm tricky, you could have an unlimited number of relationships in the chain