core data and relationship predicate - swift

Question

I've start swift & core data few month ago usually I've found my answer on this website but for the first time I'm really stuck with "Relationship" and "Predicates"
I've created a first view controller with a tableview which is populated by the user and this part is working like I wish.
The user can "tap" a cell and open a new view controller with a new tableview and I'd like populate this tableview with data that in relation with the cell the user tapped.
I'm using CoreData and I've set 2 entities : "Compte" and "Operation" they are in relationship by ONE TO MANY (ONE compte for MANY operation)
Here where I am :
when the user tap the cell i'm using segue to send the "Compte" to the second view controller :
//Segue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let guest = segue.destination as! OperationsViewController
let indexPath = tableView.indexPathForSelectedRow
let operation = fetchedResultController.object(at: indexPath!)
guest.compteTestRelation = operation
}
In the OperationsViewController i've set this variable :
var compteTestRelation: Compte!
for testing my data I've create a FOR LOOP like this and a FUNCTION:
for index in 1 ... 10 {
let newOp = Operation(context: context)
newOp.nom = "Test Compte \(index)"
newOp.date = NSDate()
newOp.moyenPaiement = "Test"
compteTestRelation.addToRelationCompte(newOp) // RelationShip
}
do {
try context.save()
} catch {
print(error.localizedDescription)
}
the FUNCTION
func displayOperation() {
if let opList = compteTestRelation.relationCompte as? Set<Operation> {
sortedOperationArray = opList.sorted(by: { (operationA:Operation, operationB:Operation) -> Bool in
return operationA.date!.compare(operationB.date! as Date) == ComparisonResult.orderedAscending
})
print(sortedOperationArray)
}
}
In the console with "print" It work like I wish depend the cell is tapped the print(sortedOperationArray) appear or not
My problem now is how populate my tableview with this data, when I use predicates in my FetchResultController I've got error or an empty tableview but in the console everything seems to work so I'm thinking the relationship is OK ..
If I don't use PREDICATE I can populate my tableview with the data but I see always ALL the data
I've seen other similar problems and answers on stackoverflow.com but nothing work for the moment.
Thank You! :)

Answer 1

I've found an another way to predicate my data and it works for me now
I've create a new attribute in my OPERATION entity called "id" and when I create my data I attribute an ID like this :
for index in 1 ... 10 {
let newOp = Operation(context: context)
newOp.nom = "Test Compte \(index)"
newOp.date = NSDate()
newOp.moyenPaiement = "Test"
newOp.id = "id123\(compteTestRelation.nom!)"
compteTestRelation.addToRelationCompte(newOp) // RelationShip
}
do {
try context.save()
} catch {
print(error.localizedDescription)
}
then I predicate my data like this in my FetchResultController :
func setupFetchedResultController () {
let operationsRequest: NSFetchRequest<Operation> = Operation.fetchRequest()
let sortDescriptor = NSSortDescriptor(key: "nom", ascending: true)
let keyPath = "id"
let searchString = "id123\(compteTestRelation.nom!)"
let operationsPredicate = NSPredicate(format: "%K CONTAINS %#", keyPath, searchString)
operationsRequest.returnsObjectsAsFaults = false
operationsRequest.sortDescriptors = [sortDescriptor]
operationsRequest.predicate = operationsPredicate
fetchedResultController = NSFetchedResultsController(fetchRequest: operationsRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
do {
try fetchedResultController.performFetch()
} catch {
print(error.localizedDescription)
}
}