实体更新后，Coredata关系中断

Question

I am using coredata to save the server data through web services in my application and I am storing relationships as an object to the entity.

I have many entities eg "Inspirations" and "Products" and both are related to each other. I have a problem whenever the records are updated in the third entity which is "Filters" then the relations of the entities broke and I cannot apply filters on the entities.

[object addRelatedInspirationsObject:related];

This is how I save relationships. I am not able to figure out why the relations are being broken once the entity is updated which has no direct link with the entity.

One thing more if I fetch and save the data of any one of the entities like "Inspirations" then all the relations start to work again.

Answer 1

From your question it seems that entities have 1 to many relationship between them. And by the code you supplied, every things should work fine. Just make sure, you are using the Filter object from the relationship like object.filter (or obj1.obj2.filter), not accessing it via a direct NSPredicate on Filter entity and updating it. And if you are using FRC, you might also need to generate a fault against the parent entities, to get your UI updates.

Answer 2

Your code should work. Here are 2 things you need to check:

• Make sure related is not nil when you call your method.
• Make sure you call save on a valid managed object context.