CODEWITHSUNDEEP
ioscore-data
LuckyStarr
LuckyStarr

Reputation: 1500

Load automatically entity of core data relationship

I have two entities A and B between which there is a 1 to n relationship (A-1---n->B). What I want to achieve is that whenever an entity A is recovered is also be automatically retrieved a specific entity B belonging to the relationship. I could think of is to create a subclass of NSManagedObject and modify it to achieve my goal but I do not know how to do that and whether it is the right solution.

Upvotes: 0

Views: 79

Answers (1)

GraemeArthur
GraemeArthur

Reputation: 517

You can get XCode to automatically generate an NSManagedObect subclass for you by going to the Editor drop down menu. Once you've generated the subclass, you can write any custom code into the generated subclass but it's often recommended to create a Category as if you need to regenerate the subclass it will wipe said custom code.

As for the retrieving of a specific entity B, you could have another relationship to entity B but this time just a 1 to 1 relationship (say "specialRelationship" for example) and tick the "transient" box (this just means that the data isn't stored in the persistent store, but is determined programmatically). In your Category, you can then write a custom accessor for specialRelationship which will programmatically choose the correct entity B to return.

Upvotes: 1

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