问题
This issue started occurring after we added Unique key i.es Constraint.
Frequently updating Meeting managed object deletes the event managed object which has a to-one inverse relationship from meeting managed object.
Error CoreData: annotation: repairing missing delete propagation for to-many relationship meetingList on object 0x60c00009c4d0 (0x60c000621e40 ) with bad fault 0x60800009ac20 (0x60800023a360 )
Data Model
I have three entities in my core data model i.es
(CDEvent, CDMeeting, CDMLCheckin) .
Entity Properties and Relationship as described below:
Relationship
Properties: CDEvent CDMeeting
CDMLCheckin
Unique Constraint:
- CDEvent entity has eventUUID as unique constraint.
- CDMeeting entity has meetingUUID as unique constraint.
Relationship
- CDEvent <->>CDMeeting
- From CDEvent to CDMeeting is to-many relationship with delete rule cascade, inverse relationship from CDMeeting to CDEvent is to-one with delete rule nullify.
- CDEvent <->>CDMLCheckin
- From CDEvent to CDMLCheckin is to-many relationship with delete rule cascade, inverse relationship from CDMLCheckin to CDEvent is to-one with delete rule nullify.
Full Description : https://docs.google.com/document/d/1y2DQhBBLqjAP9eWbx5YpQhH7oVigxT_mcJDnPLlOMtQ/edit?usp=sharing
Note
- If i remove Unique Constraint eventUUID from CDEvent everything works fine.
Please help us here as we are struck from more than a week :(
回答1:
I hope I can help, having a unique constraint with To-Many Relationship Entities you need to keep some points in mind
- Use Inverse Relationship of every CoreData relation
- Unique Constrains Attributes should never be Optional
When you create NSManagedObjectContext make sure you set MergePolicy.
[_context setMergePolicy: mergePolicy];
NSMergeByPropertyStoreTrumpMergePolicy
NSMergeByPropertyObjectTrumpMergePolicy
NSOverwriteMergePolicy
Also could you try changing the nullify delete rule to no action ?
来源：https://stackoverflow.com/questions/49129364/core-data-after-adding-unique-constraint-annotation-repairing-missing-delet