ios – 在Swift中添加一个许多关系

现在在代码中我也创建了NSManagedobject子类,并能够分别创建这个对象.所有我需要帮助的是我如何创建关系.我的代码是

Xcode生成Father.swift

class Father: NSManagedobject {

    @NSManaged var name: String
    @NSManaged var fathertochild: NSSet

}

Xcode生成Child.swift

class Child: NSManagedobject {

    @NSManaged var name: String
    @NSManaged var child_father: NSManagedobject

}

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)

}