Question

Don’t know if you got my question, so here is an example.

I have an array with 50 product IDs and I want to check if all IDs exist in Core Data. How would I do that without a loop and making 50 requests? There must be a more efficient way than that I think.

In my model I have an entity Product with just Name and Id attributes.

Answer 1

You can use…

[fetchRequest setPredicate:[NSPredicate predicateWithFormat: @"productid IN[c] %@", ids]];

where ids is an array of NSStrings and fetchRequest is you NSFetchRequest on the entity with the property productid.

You can also do this for other object types and for relationships.

i.e.

NSArray *requiredChildren = //some array of coredata objects

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"child IN %@", requiredChildren];