Preventing duplicate storage to realm - ios

Question

I am using realm to store and persist my data. Everything works fine and I just discovered that users can actually store duplicate item which is bad. I would am unable to create a check to prevent duplicate items, any help would be appreciated
Function
func addData(object: OfflineModel) {
try! database.write {
database.add(object, update: true)
}
}
//MARK:- Get Offline
func getDataFromDB() -> Results<OfflineModel> {
offlineItems = database.objects(OfflineModel.self)
return offlineItems!
}
//MARK:- Create Offline
func createOfflineList(createdDate: Date, photo: Data, title: String, completion: #escaping CompletionHandler) -> Void {
REALM_QUEUE.sync {
let offlineList = OfflineModel()
offlineList.createdDate = createdDate
offlineList.photo = photo
offlineList.title = title
OfflineFunctions.instance.addData(object: offlineList)
completion(true, nil)
}
}
Model
#objc dynamic var id = UUID().uuidString
#objc dynamic var photo: Data? = nil
#objc dynamic var title : String = ""
#objc dynamic var createdDate: Date?
override static func primaryKey() -> String {
return "id"
}

Answer 1

The issue is that in the createOfflineList method you create a new OfflineModel, which generates a random id using UUID().uuidString and hence you cannot have duplicate models from Realm's point of view, since id, which is used as the primary key will always be different. You'll need to use title (or any other non-random property that you actually want to use to identify your model instances) as the primary key.
class OfflineModel: Object {
#objc dynamic var photo: Data? = nil
#objc dynamic var title : String = ""
#objc dynamic var createdDate: Date?
override static func primaryKey() -> String {
return "title"
}
}