Adding one read only attribute to Core Data Model in Swift. Which doesn't exist in XCDataModel

Question

Adding attribute to entity which don't exist in XCDataModel was easily accomplised VIA @synthesize and @dynamic in objective c. Please guide how to achieve this in swift.

@NSManaged public var salesPrice: NSNumber?
public var totalVal: NSNumber {
   get {
       return salesPrice ?? NSNumber(value: 0)
   }
}

Here sales price is managed but totalVal is not managed nor exist in xcDataModel. I am getting crash 'The entity is not key value coding-compliant for the key 'totalVal' on accessing totalVal.

if let coreObj = indItem.parentObj.value(forKey: keyPath) { }

Crash happening here.

• 'indItem.parentObj' this is right object (I double checked)
• 'keyPath' is 'totalVal' (I copied it rightly)

Answer 1

To support key-value coding for a type declared in Swift, you have to mark it with the @objc keyword:

@objc public var totalVal: NSNumber {