Coredata relationship issue

Question

I\'m facing a weird issue with my core data. I\'ve the following relationship

A contact can belong to one category and a category can have multiple contacts. I\'d like

Answer 1

The category property of a Contact object is a Category object. But you are trying to set it to be a String (categoryField.text). You probably want to use a Category object whose name is equal to categoryField.text.

You could create one:

    let categoryEntity = NSEntityDescription.entityForName("Category", inManagedObjectContext: context!)
    let newCategory = Category(entity: categoryEntity!, insertIntoManagedObjectContext: context)
    newCategory.name = categoryField.text
    // set the other properties for the Category as necessary
    // then assign the relationship
    newContact.category = newCategory

But you might already have created a Category with that name. So the usual approach would be to search for a Category with the right name, use that if it exists, or create a new Category if not:

    let categoryEntity = NSEntityDescription.entityForName("Category", inManagedObjectContext: context!)
    let fetchRequest = NSFetchRequest()
    fetchRequest.entity = categoryEntity!
    fetchRequest.predicate = NSPredicate(format:"name == %@",categoryField.text)
    let fetchResults = try? context!.executeFetchRequest(fetchRequest)
    if let results = fetchResults {
        var requiredCategory : Category
        if (results.count > 0) {
            requiredCategory = results[0] as! Category
        } else {
            requiredCategory = Category(entity: categoryEntity!, insertIntoManagedObjectContext: context!)
            requiredCategory.name = categoryField.text
            // set the other properties for the Category as necessary
        }
        newContact.category = requiredCategory
    }