Swift Core Data - Request with distinct results

Question

how I can call es request with distinct values in swift?

This is my code:

let appDelegate: AppDelegate = UIApplication.sharedApplication().delegate a         


        

Answer 1

NSPredicate will allow you to search for specific values and retrieve only the data you need from core data:

  var StoredResults = [NSManagedObject]()

  func fetchRequest(docID : String ){

        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let managedContext = appDelegate.managedObjectContext
        let request = NSFetchRequest(entityName: "EntityContainingDocID")

        let predicate =  NSPredicate(format:"docID == %@", docID)
        request.predicate = predicate

    do {
        let results =
        try managedContext.executeFetchRequest(request)

        StoredResults = results as! [NSManagedObject]

        } catch let error as NSError {
              print(" error executing fetchrequest  ", error)
        }
    }

In this example we are only looking to return specific values matching a string in the "docID" column but NSPredicate is a handy way of building SQL-like queries into your code and is pretty flexible.