I have the following (simplified) Realm Models:
final class Item: Object {
#objc dynamic var identifier: String = ""
#objc dynamic var programSet: ProgramSet?
override static func primaryKey() -> String? {
return "identifier"
}
}
final class ProgramSet: Object {
#objc dynamic var identifier: String = ""
#objc dynamic var editorialCategory: EditorialCategory?
override static func primaryKey() -> String? {
return "identifier"
}
}
final public class EditorialCategory: Object {
#objc dynamic var identifier: String = ""
override public static func primaryKey() -> String? {
return "identifier"
}
}
final class Playlist: Object {
#objc dynamic var id = UUID().uuidString
#objc dynamic var name = ""
#objc dynamic var created = Date()
var items = List<Item>()
override static func primaryKey() -> String? {
return "id"
}
}
When the user adds an item to a playlist, I try to append the ItemModel to the Playlist.items List:
try realm.write {
playlistToModify.items.append(item)
}
My problem is that it's possible for Items to share the same EditorialCategory, so it may already be in the database. When I add other items via the Realm.add(_:update:) method, Realm won't try to recreate the linked objects if one with the same primary key exists.
The List.append(_:) method seems to force recreating the linked objects of an ItemModel when called. The app crashes in the following line from object_accessor.hpp:
throw std::logic_error(util::format("
Attempting to create an object of type '%1' with an existing primary key value '%2'.",
object_schema.name, ctx.print(*primary_value)));
Stacktrace:
The object_schema.name is "EditorialCategoryModel", which is linked in ProgramSetModel, which itself is linked from ItemModel.
Is there a way to avoid this error and append the item to the list without Realm attempting to re-create every linked object? Thanks!
Related
I'm trying to provide some data in the cloud with Firestore that can be downloaded and stored in a Realm database on an iOS device.
The structure of my object that I want to store is:
import Foundation
import RealmSwift
import FirebaseFirestore
import FirebaseFirestoreSwift
#objcMembers class Flashcard: Object, Codable{
#objc dynamic var id: String? = NSUUID().uuidString
#objc dynamic var character: String?
#objc dynamic var title: String?
#objc dynamic var translation: String?
#objc dynamic var created: Date = Date()
let deck = LinkingObjects<FlashcardDeck>(fromType: FlashcardDeck.self, property: "cards")
override class func primaryKey() -> String? {
return "id"
}
private enum CodingKeys: String, CodingKey {
case id
case character
case translation
case created
case title
}
If I try to map the documentID to my id attribute with
#DocumentID #objc dynamic var id: String? = NSUUID().uuidString
If get the following error:
'Primary key property 'id' does not exist on object 'Flashcard'
How can I solve this problem?
EDIT: To make it more understandable here is a screenshot of my Firestore database:
The collection "PredifinedDecks" will store many decks. For example the id = DF59B1B3-BD22-47CE-81A6-04E7A274B98F represents one deck. Each deck will store an array/List with cards in it.
Not sure I fully understand the question but let me address this at a high level.
It appears there is a PredefinedDecks (a collection) that contains documents. Each document has a field (an array) of cards and some other field data. If the goal is to read in all of the documents (the decks) and their child data and store them as Realm objects, here's one solution. Start with a Realm object to hold the data from Firestore
class DeckClass: Object {
#objc dynamic var deck_id = ""
#objc dynamic var created = ""
#objc dynamic var title = ""
let cardList = List<CardClass>()
convenience init(withDoc: QueryDocumentSnapshot) {
self.init()
self.deck_id = withDoc.documentID
self.title = withDoc.get("title") as? String ?? "no title"
self.created = withDoc.get("created") as? String ?? "no date"
let cardArray = withDoc.get("cards") as? [String]
for card in cardArray {
let card = CardClass(withCard: card) {
self.cardList.append(card)
}
}
}
}
With this, you simply pass the documentSnapshot from Firestore for each document and the class will populate its properties accordingly.
and the code to read Firestore
func readDecks() {
let decksCollection = self.db.collection("PredefinedDecks")
decksCollection.getDocuments(completion: { documentSnapshot, error in
if let err = error {
print(err.localizedDescription)
return
}
for doc in documentSnapshot!.documents {
let deck = DeckClass(withDoc: doc)
self.decksList.append(deck) //a Realm List class object? Something else?
}
})
}
I am attempting to implement a GKGameModel in my application. In it, it holds variables to a few things, but for the purposes of my question I'm interested in the following two variables:
import GameplayKit
final class GameModel: NSObject, GKGameModel {
var players: [GKGameModelPlayer]?
var activePlayer: GKGameModelPlayer?
}
I do something like this to initialise the game with 3 players (not exact)
let game = GameModel.init()
game.players = [Player(),Player(),Player()] // Create 3 players
guard let firstPlayer = game.players.first else {
return
}
game.activePlayer = firstPlayer
A player class is defined as:
class Player : NSObject, GKGameModelPlayer {
var playerId: Int // GKGameModelPlayer protocol variable
let name: String
var cash: Int = 0
}
In my project I have Realm Entities and the models seperated. So there will be a PlayerEntity and a Player class.
I'm wanting to use RealmSwift to save and load the GKGameModelPlayer data, and more specifically the ability to store/re-store the active player.
I think the key here is the playerId variable; but I am not sure.
But what I'm not sure about is retrieving this information and then re-mapping it into a valid GKGameModelPlayer format
My current idea/theory is that I need to map my model to an entity class and vice-versa.
Ie:
// [REALM] Player entity
class PlayerEntity: Object {
#objc dynamic var id = UUID().uuidString
#objc dynamic var playerId: Int = 0
#objc dynamic var name: String = ""
#objc dynamic var cash: Int = 0
override static func primaryKey() -> String {
return "id"
}
}
And then I extend this class to do some "mapping":
extension PlayerEntity {
// Map model -> entity
convenience init(model: Player) {
self.init()
self.playerId = model.playerId
self.name = model.name
self.cash = model.cash
}
}
extension Player {
// Map entity -> model
convenience init(entity: PlayerEntity) {
let playerId = entity.playerId
let name = entity.name
let cash = entity.cash
self.init(id: playerId, name: name, cash: cash)
}
}
Right now, the playerId is always zero (0) because I'm not really sure how to set it.
I can save a player to realm.
The issue comes from when I try to restore the player, and I want to restore the activePlayer variable in the GameModel
Therefore, my question is:
How would I go about saving and restoring the activePlayer variable so that it continues to comply to GKGameModelPlayer?
I appreciate any assistance on this.
With thanks
While you could use those extensions, sometimes simpler is better. Here's a rough example:
class PlayerEntity: Object {
#objc dynamic var playerId: Int = 0
#objc dynamic var name: String = ""
#objc dynamic var cash: Int = 0
convenience init(withPlayer: PlayerClass) {
self.init()
self.playerId = withPlayer.playerId
self.name = withPlayer.name
self.cash = withPlayer.cash
}
func getPlayer() -> Player {
let p = Player()
p.playerId = self.playerId
p.name = self.name
p.cash = self.cash
return p
}
override static func primaryKey() -> String {
return "playerId"
}
}
to load all the players into an array... this will do it
let playerResults = realm.objects(PlayerEntity.self)
for player in playerResults {
let aPlayer = player.getPlayer()
self.playerArray.append(aPlayer)
}
Notice the removal of
#objc dynamic var id = UUID().uuidString
because it's not really being used to identify the object as a primary key.
The primary key is really
var playerId: Int // GKGameModelPlayer protocol variable
which is fine to use as long as it's unique.
I have an object with the following structure:
class REObject:Object {
dynamic var id = ""
dynamic var status = ""
override static func primaryKey() -> String? {
return "id"
}
}
The flow is: I get an array of items from the BE, the user can enter the object's id and change the status.
And the question is: how could get the item with case-insensitive id?
if let item = realm.object(ofType: REObject.self, forPrimaryKey: id) {
return item
}
Override isSameObjectAs in your class and compare lowercase (or uppercase) versions of id there
I have a realm object called DiscoverUserInfo:
class DiscoverUserInfo: Object , Mappable{
dynamic var UserObject:User?
dynamic var ConnectionStatus:Int = -1
var PreviousMeetings = List<Meeting>()
required convenience init?(map: Map) {
self.init()
}
override class func primaryKey() -> String? { return "UserObject.UserId" }
}
Now for this, I want to set a primary key which is UserId of UserObject.
But when I run this code, I get this error:
Terminating app due to uncaught exception 'RLMException', reason:
'Primary key property 'UserObject.UserId' does not exist on object
'DiscoverUserInfo''
You cannot set a primary key using a property of a dynamic variable. You'll have to do something like this:
class DiscoverUserInfo: Object , Mappable{
dynamic var UserObject: User?
dynamic var id = ""
dynamic var ConnectionStatus:Int = -1
var PreviousMeetings = List<Meeting>()
required convenience init?(map: Map) {
self.init()
}
override class func primaryKey() -> String? {
return "id"
}
}
and then set the id to the associated UserObject's UserId each time you create a new DiscoverUserInfo object.
This is related to the issue of having no native support for compound primary keys in Realm. However, we expect to see this feature down the road.
I found this great solution for using Realm with compound primary key in Swift: https://github.com/realm/realm-cocoa/issues/1192
public final class Card: Object {
public dynamic var id = 0 {
didSet {
compoundKey = compoundKeyValue()
}
}
public dynamic var type = "" {
didSet {
compoundKey = compoundKeyValue()
}
}
public dynamic lazy var compoundKey: String = self.compoundKeyValue()
public override static func primaryKey() -> String? {
return "compoundKey"
}
private func compoundKeyValue() -> String {
return "\(id)-\(type)"
}
}
But I discovered that Realm does not support lazy properties, in my case I receive this error:
exception NSException * name: "RLMException" - reason: "Lazy managed property 'compoundKey' is not allowed on a Realm Swift object class. Either add the property to the ignored properties list or make it non-lazy." 0x00007f8a05108060
Is it still possible to have compound key without lazy property?
The solution you found is outdated. I'll leave a note about that there. I'd suggest removing the lazy modifier and initializing compoundKey to an empty string.