ios - How to set primary key in Swift for Realm model

Question

I'm using Realm in a new iOS Swift project. I'm using Xcode 6.0.1 with iOS SDK 8.0 and Realm 0.85.0

I'm trying to use the new Realm primary key feature so I can do an addOrUpdateObject.

Here is a sample model:

import Foundation
import Realm

class Foo: RLMObject {
    dynamic var id = 0
    dynamic var title = ""

    func primaryKey() -> Int {
        return id
    }
}

And how I'm trying to add/update a new object:

let foo = Foo()
foo.title = titleField.text
foo.id = 1

// Get the default Realm
let realm = RLMRealm.defaultRealm()

// Add to the Realm inside a transaction
realm.beginWriteTransaction()
realm.addOrUpdateObject(foo)
realm.commitWriteTransaction()

I get this error:

RLMExecption', reason: ''Foo' does not have a primary key and can not be updated

Here are the docs on the primary key. I'm probably not setting it correctly: http://realm.io/docs/cocoa/0.85.0/api/Classes/RLMObject.html#//api/name/primaryKey

Latest docs are here now: https://realm.io/docs/objc/latest/api/Classes/RLMObject.html#//api/name/primaryKey

question from:https://stackoverflow.com/questions/26152254/how-to-set-primary-key-in-swift-for-realm-model

Answer 1

primaryKey needs to be a class function which returns the name of the property which is the primary key, not an instance method which returns the value of the primary key.

@objcMembers class Foo: RLMObject {
    dynamic var id = 0
    dynamic var title = ""

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