How to define my Primary Key?

Question

I am developing an application in Swift and started using the Core Data recently. I need to define which attribute of my entity will be mine Primary key. For example:

I have an entity that has class attributes:

• id
• name
• age

I need the attribute "id" to be mine Primary key.

It may be in Objective-C really, I just need to know how I define it.

Answer 1

//Swift

  class Foo: RLMObject {
        dynamic var id = 0

        override class func primaryKey() -> String {
            return "id"
        }
    }

//Core data

[https://stackoverflow.com/questions/901640/core-data-primary-key]