CODEWITHSUNDEEP
iosswiftcore-dataswift2nsfetchrequest
icekomo
icekomo

Reputation: 9466

How to handle fetch requests in CoreData when you know there are no Entities saved

I have an app that I know the first time it runs there will be nothing saved in CoreData. I am trying to check for that scenario like this:

let fetchRequest = NSFetchRequest(entityName: "Person")

    let error = NSErrorPointer()

    do{
        let fetchResults = (try! coreDataStack.context.countForFetchRequest(fetchRequest, error: error))
        print("Count \(fetchResults)")
    } catch let error as NSError{
        print("Fetch failed: \(error.localizedDescription)")
    }

I get a warning saying "Cast from "Int" to unrelated type '[Person]' always fails.

I'm just not sure what I'm missing. I'm sure checking for any Entities in CoreData is a common practice.

Upvotes: 1

Views: 169

Answers (2)

Sohel L.
Sohel L.

Reputation: 9540

You don't need to convert that into [Entity] because the countForFetchRequest returns the number of counts. So, you need need to call without casting.

let fetchResults = coreDataStack.context.countForFetchRequest(fetchRequest, error: error)
print("Count \(fetchResults)")

Upvotes: 3

icekomo
icekomo

Reputation: 9466

I was able to use this code to get the countForFetchRequest working:` let fetchRequest = NSFetchRequest(entityName: "Person")

    var error: NSError?

    let count = coreDataStack.context.countForFetchRequest(fetchRequest, error: &error)

    if count != NSNotFound {
        print("Count \(count)")
    } else {
        print("Could not fetch \(error), \(error?.userInfo)")
    }`

Upvotes: 0

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