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

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

Answer 1

As of Realm Swift v10.10.0, you declare a primary key with #Persisted(primaryKey: true):
class Foo: Object {
#Persisted(primaryKey: true) var id = 0
#Persisted var title = ""
}
Older versions:
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"
}
}

Answer 2

The return type of primaryKey() is optional:
class Foo: RLMObject {
dynamic var id = 0
dynamic var title = ""
override class func primaryKey() -> String? {
return "id"
}
}

Answer 3

For Swift 5:
import RealmSwift
class Signature: Object {
#objc dynamic var id = ""
override static func primaryKey() -> String? {
return "id"
}
}
To avoid: Terminating app due to uncaught exception 'RLMException', reason: 'Primary key property 'id' does not exist on object.

Answer 4

Realm 10.12.0 & Swift 5
Legacy property declarations using #objc:
import RealmSwift
class Signature: Object {
#objc dynamic var id = ""
override static func primaryKey() -> String? {
return "id"
}
}
When using #Persisted, use #Persisted(primaryKey: true) instead:
import Foundation
import RealmSwift
class MyModel: Object {
#Persisted var pan: String?
#Persisted var exp: String?
#Persisted var cvv: String?
#Persisted(primaryKey: true) var myId: String?
override init() {}
init(pan: String, exp: String, cvv2: String) {
super.init()
self.pan = pan
self.exp = exp
self.cvv = cvv2
}
}