Swift Core Data 只保存与循环中最后一个的关系

Question

我有以下数据模型：

Checklist
@NSManaged var date: NSTimeInterval
@NSManaged var day: Int16
@NSManaged var items: NSSet?

和

ChecklistItem
@NSManaged var completed: Bool
@NSManaged var dayType: Int16
@NSManaged var itemName: String?
@NSManaged var timeOfDay: String?
@NSManaged var checklist: Checklist?

我正在尝试将 ChecklistItems 数组 (NSSet) 保存到新的 Checklist 对象中。这是我的代码：

    var tasksHolder = [ChecklistItem]()

    let moc = CoreDataStack.sharedInstance.managedObjectContext

    //puts one day's worth of tasks into the array
    for (index, item) in tasks.enumerate() {

        let newTask = NSEntityDescription.insertNewObjectForEntityForName(String(ChecklistItem), inManagedObjectContext: moc) as! ChecklistItem
        newTask.completed = false
        newTask.dayType = DayType.ShakeDay.rawValue
        newTask.itemName = item
        newTask.timeOfDay = times[index]

        do {
            try moc.save()
        } catch {
            print("error")
        }

        tasksHolder.append(newTask)
    }

    //do each day
    for i in 0..<30 {

        let set = NSSet(array: tasksHolder)

        let newChecklist = NSEntityDescription.insertNewObjectForEntityForName(String(Checklist), inManagedObjectContext: moc) as! Checklist
        newChecklist.date = NSDate().timeIntervalSince1970
        newChecklist.day = Int16(i)
        newChecklist.items = set

        do {
            try moc.save()
        } catch {
            print("error")
        }
    }

实际的清单对象保存得很好，我遇到问题的是关系。 ChecklistItem 关系仅保存到清单的第 30 个（最后一个）元素。我不确定为什么会这样，但我假设它与我向 Checklist 对象添加内容的方式有关。

非常感谢任何帮助。

Answer 1

我不知道这是否是您所拥有内容的最佳选择，但您可以在嵌套的 for 循环中添加关系，如下所示；

//do each day
for i in 0..<30 {

    let newChecklist = NSEntityDescription.insertNewObjectForEntityForName(String(Checklist), inManagedObjectContext: moc) as! Checklist
    newChecklist.date = NSDate().timeIntervalSince1970
    newChecklist.day = Int16(i)

    for i in 0..<taskHolder.count {
        let items = newChecklist.mutableSetValueForKey("items")
        items.addObject(taskHolder[i])
    }

    do {
        try moc.save()
    } catch {
        print("error")
    }
}

Swift Core Data 只保存与循环中最后一个的关系

Swift Core Data only saving relationship to the last in the loop

ios

swift

core-data

xcode7

relationships