fetch with predicate always return nil

Question

I have two entities, one is "Object" another is "Logo", and they have got a relationship one to one. When i am adding some Logo to core data i want to check if my Object already has one. So I making predicate and fetch with it. But my result is always 0, so there is no such Logos with logo.object.id == id.

I am sure that they are there, so I am not sure about this code. Maybe predicate is wrong? Can you give some advice?

class func fetchLogoWithId(moc: NSManagedObjectContext, id: Int64) -> Logo? {
        var fetchRequest = NSFetchRequest(entityName: "Logo")
        fetchRequest.predicate = NSPredicate(format: "object.id == %d", id)

        var error: NSError?

        if moc.countForFetchRequest(fetchRequest, error: &error) == 0 {
            return nil
       }

        var logo = moc.executeFetchRequest(fetchRequest, error: &error)
        if error != nil {
            return nil
        }

        println("--------------")
        println(logo)
        println("--------------")
        return logo?.first as? Logo
    }

How is the "id" property defined in the Core Data model inspector? Does the fetch request return something if you *don't* add a predicate? Is the wanted object among the results? — Martin R, Jun 20 '15 at 17:08
Activate Core Data SQLite debugging (http://stackoverflow.com/questions/12306343/how-to-print-core-data-debug-values) and add the output to your question. — Martin R, Jun 20 '15 at 17:23
You should also show how you call this function and make sure you pass the ID you think you are passing. — Mundi, Jun 21 '15 at 11:57

score 2 · Answer 1 · answered Jun 20 '15 at 17:59

2

I am a bit guessing, but the problem could be that the %d format formats a C int value, which is a 32-bit quantity on a 32-bit device. For 64-bit integer, you should replace the predicate by

NSPredicate(format: "object.id == %lld", id)

or

NSPredicate(format: "object.id == %@", NSNumber(longLong: id))

answered Jun 20 '15 at 17:59

Martin R

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@user3224534: What about the debugging that I suggested in a comment to your question? – Martin R Jun 20 '15 at 19:23

fetch with predicate always return nil

1 Answers1