境界不坚持写入的变化

Question

我有一个函数，我通过一个payment和一个debt对象（都是代表我的Realm数据库中的数据的结构）。然后，我想将payment附加到debt的paymentHistory。下面是我用这个代码：

static func savePayment(payment: Payment, forDebt debt: Debt) throws { 
    let realm = try Realm() 
    let predicate = NSPredicate(format: "created = %@", debt.created) 
    guard let dbDebt = realm.objects(DBDebt.self).filter(predicate).first else { fatalError("no debt found in DB for payment") } 
    let dbPayment = DBPayment(payment: payment) 
    try realm.write { 

    // first try 
    // dbDebt.paymentHistory.append(dbPayment) 

    // second try 
    let newPaymentHistory = dbDebt.paymentHistory 
    newPaymentHistory?.append(dbPayment) 
    dbDebt.paymentHistory = newPaymentHistory 
    } 
} 

注意，我包括在两次尝试我做了，无论这实际上持续数据的代码（我检查这个使用领域浏览器）。

另请注意，在调试时，我可以看到DBPayment已创建并正确地追加到dbDebt的列表中。也许我失去了一些东西很明显，但我希望这在领域documentation因为工作，他们声明如下：

对于参考，这里是定义我的结构和数据库对象：

class DBDebt: Object { 

    dynamic var amount: Double = 0.0 
    dynamic var owner: DBPerson? = DBPerson() 
    var paymentHistory: List<DBPayment>? = List<DBPayment>() 
    dynamic var currency: String = Currency.Dollar.rawValue 
    dynamic var created: NSDate = NSDate() 
    dynamic var deadline: NSDate? = nil 

    init(debt: Debt) { 
    self.amount = debt.amount 
    self.owner = DBPerson(person: debt.owner) 
    self.paymentHistory = debt.paymentHistory.reduce(List<DBPayment>()) { (list: List<DBPayment>, payment: Payment) in 
     list.append(DBPayment(payment: payment)) 
     return list 
    } 
    self.currency = debt.currency.rawValue 
    self.created = debt.created 
    self.deadline = debt.deadline 
    super.init() 
    } 

    required init(value: AnyObject, schema: RLMSchema) { 
    super.init(value: value, schema: schema) 
    } 

    required init(realm: RLMRealm, schema: RLMObjectSchema) { 
    super.init(realm: realm, schema: schema) 
    } 

    required init() { 
    super.init() 
    } 

} 

class DBDebt: Object { 

    dynamic var amount: Double = 0.0 
    dynamic var owner: DBPerson? = DBPerson() 
    var paymentHistory: List<DBPayment>? = List<DBPayment>() 
    dynamic var currency: String = Currency.Dollar.rawValue 
    dynamic var created: NSDate = NSDate() 
    dynamic var deadline: NSDate? = nil 

    init(debt: Debt) { 
    self.amount = debt.amount 
    self.owner = DBPerson(person: debt.owner) 
    self.paymentHistory = debt.paymentHistory.reduce(List<DBPayment>()) { (list: List<DBPayment>, payment: Payment) in 
     list.append(DBPayment(payment: payment)) 
     return list 
    } 
    self.currency = debt.currency.rawValue 
    self.created = debt.created 
    self.deadline = debt.deadline 
    super.init() 
    } 

    required init(value: AnyObject, schema: RLMSchema) { 
    super.init(value: value, schema: schema) 
    } 

    required init(realm: RLMRealm, schema: RLMObjectSchema) { 
    super.init(realm: realm, schema: schema) 
    } 

    required init() { 
    super.init() 
    } 

} 


struct Payment { 

    init(amount: Double, paymentDate: NSDate = NSDate()) { 
    self.amount = amount 
    self.paymentDate = paymentDate 
    } 

    let amount: Double 
    let paymentDate: NSDate 

} 

class DBPayment: Object { 

    dynamic var amount: Double = 0.0 
    dynamic var paymentDate: NSDate = NSDate() 

    init(payment: Payment) { 
    self.amount = payment.amount 
    self.paymentDate = payment.paymentDate 
    super.init() 
    } 

    required init(value: AnyObject, schema: RLMSchema) { 
    super.init(value: value, schema: schema) 
    } 

    required init(realm: RLMRealm, schema: RLMObjectSchema) { 
    super.init(realm: realm, schema: schema) 
    } 

    required init() { 
    super.init() 
    } 

} 

Answer 1

为了坚持对象的领域，你必须调用你的领域add()函数（docs）。

下面应该工作：

try realm.write { 

    // this persists your dbPayment in your realm! 
    realm.add(dbPayment) 

    // first try 
    // dbDebt.paymentHistory.append(dbPayment) 

    // second try 
    let newPaymentHistory = dbDebt.paymentHistory 
    newPaymentHistory?.append(dbPayment) 
    dbDebt.paymentHistory = newPaymentHistory 
}