在Swift中添加一对多关系

I am new to iOS programming and just need a small help. I am trying to use core data and create a simple insert where there is a one to many relation ship. My very simple core data structure looks like this

我是iOS编程的新手，只需要一点帮助。我正在尝试使用核心数据并创建一个简单的插入，其中存在一对多的关系。我非常简单的核心数据结构如下所示

Now in the code i have created NSManagedObject subclass as well and am able to create this objects individually. All i need help is how do i create the relationship. My code is is

现在在代码中我也创建了NSManagedObject子类，并且能够单独创建这些对象。我需要帮助的是如何创建关系。我的代码是

Xcode generated Father.swift

Xcode生成了Father.swift

class Father: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var fatherToChild: NSSet

}

Xcode generated Child.swift

Xcode生成了Child.swift

class Child: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var child_father: NSManagedObject

}

My Add Data method:

我的添加数据方法：

    func addData(){
   var appDel: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
   var context: NSManagedObjectContext = appDel.managedObjectContext!

    var fatherEntity = NSEntityDescription.entityForName("Father", inManagedObjectContext: context)
    var newFather = Father(entity: fatherEntity, insertIntoManagedObjectContext: context)
    newFather.name = "Daddy"


    var childEntity = NSEntityDescription.entityForName("Child", inManagedObjectContext: context)
    var child1 = Child(entity: childEntity, insertIntoManagedObjectContext: context)
    child1.name = "child1"
    var child2 = Child(entity: childEntity, insertIntoManagedObjectContext: context)
    child2.name = "child2"

    //How to map these 2 childs to father? Need help in code here!

    context.save(nil)

}   

1 个解决方案

#1

All you have to do is to set the relationship from Child to Father:

你所要做的就是设置从孩子到父亲的关系：

child1.child_father = newFather
child2.child_father = newFather

This automatically updates the (inverse) relationship in newFather.

这会自动更新newFather中的（反向）关系。