我有两个 Realm 模型类

class ModelA: Object {
    let id = RealmOptional<Int>()
    dynamic var name: String!
    // some other variables that are also String! type
}

class ModelB: Object {
    let id = RealmOptional<Int>()
    let models = List<ModelA>()
    // other variables
}

我有一些 JSON 对象，其中包含该模型的数据。我创建 ModelB 实例，然后用 ModelA 实例列表填充它，方法如下:

let json: JSON = ... // get it from somewhere, then use SwiftyJSON
let myModelB = ModelB()
myModelB.id.value = json["id"].object as? Int
// set other properties
let modelsA = json["models"].map { ModelA(value: $0.1.object) }
myModelB.models.appendContentsOf(modelsA)

我在这里使用不同方法的原因是 JSON 中的属性名称与我的 ModelB 属性名称不匹配，但 ModelA没关系。 稍后我在某个地方使用 realm.add(objects, update: true) (在 realm.write 内)并导致以下异常:

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ valueForUndefinedKey:]: this class is not key value coding-compliant for the key (null).'

根据documentation :

If your model class includes a primary key, you can have Realm intelligently update or add objects based off of their primary key values using Realm().add(_:update:).

因此 ModelA 和 ModelB 都具有 primaryKey() 函数，我认为这应该有效，但事实并非如此。

此外，我在调用中删除了 update 参数，并在添加新对象之前添加了对 realm.deleteAll() 的调用(均在 write 回调)。在那种情况下，我得到以下异常:

Terminating app due to uncaught exception 'RLMException', reason: 'Can't set primary key property 'id' to existing value 'xxxxxxx'.

此外，如果我尝试遍历调用堆栈，Xcode 会崩溃。如果我尝试检查调试器中的任何 Realm 对象，它也会崩溃。我已经安装了 Realm Xcode 插件，但没有任何变化。我无法理解这里出了什么问题以及为什么我会出现如此奇怪的行为。有人可以告诉我我的错误在哪里吗？

最佳答案

我从头开始项目，基于 example project .所以我完成了:

import UIKit
import RealmSwift

// Dog model
class Dog: Object {
    dynamic var name = ""
    dynamic var age = 0
    dynamic var owner: Person? // Properties can be optional

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

// Person model
class Person: Object {
    dynamic var name = ""
    let dogs = List<Dog>()

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

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.

        do {
            try NSFileManager.defaultManager().removeItemAtPath(Realm.Configuration.defaultConfiguration.path!)
        } catch {}

        let dogRexJSON: AnyObject = ["name": "Rex", "age" : 20]
        let dogLuckyJSON: AnyObject = ["name": "Lucky", "age" : 25]
        var somePerson = Person(value: ["name" : "Shurik", "dogs" : [dogRexJSON]])


        // Realms are used to group data together
        let realm = try! Realm() // Create realm pointing to default file

        // Save your object
        realm.beginWrite()
        realm.add(somePerson)
        try! realm.commitWrite()

        somePerson = Person(value: ["name" : "Shurik", "dogs" : [dogRexJSON, dogLuckyJSON]])
        try! realm.write { () -> Void in
            realm.add([somePerson], update: true)
            return
        }

        let val = realm.objectForPrimaryKey(Dog.self, key: "Lucky")
        print(val!.name) // as expected log >> Lucky

        return true
    }
}

似乎一切正常。

关于ios - 更新 Realm 对象的问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35018084/