如何在Swift中分配CoreData多对多关系？ [英] How to assign CoreData many-to-many relationship in Swift?

问题描述

我有一个NSManagedObject类

  class Disease：NSManagedObject {
 @NSManaged var diseaseId：String 
 @NSManaged var diseaseName：String 
 @NSManaged var dogBreed：NSSet 
} 
  

如何向dogBreed添加新关系？如果我将var类型更改为NSMutableSet，更改不会保存到数据库。任何想法？

解决方案

从Xcode 7和Swift 2.0开始，发布说明 17583057状态：

NSManaged属性可以与方法以及
属性一起使用，用于访问Core Data自动生成的
Key-Value-Coding兼容的许多访问器。

  @NSManaged var employees：NSSet 
 
 @NSManaged func addEmployeesObject（employee：Employee）
 @NSManaged func removeEmployeesObject（employee：Employee）
 @NSManaged func addEmployees（employees：NSSet）
 @NSManaged func removeEmployees（employees：NSSet）
  

这些可以在你的NSManagedObject子类中声明。 （17583057）

所以你只需要声明以下方法，CoreData将处理其余的操作：

@NSManaged func addDogBreedsObject（dogBreed：DogBreed）
@NSManaged func removeDogBreedsObject（dogBreed：DogBreed）
@NSManaged func addDogBreeds ：NSSet）
@NSManaged func removeDogBreeds（dogBreeds：NSSet）


I have a NSManagedObject class

class Disease: NSManagedObject {
    @NSManaged var diseaseId: String
    @NSManaged var diseaseName: String
    @NSManaged var dogBreed: NSSet
}

How do I add a new relationship to dogBreed? If i change var type to NSMutableSet, the changes are not saved to database. Any ideas?

解决方案

As of Xcode 7 and Swift 2.0, the release note 17583057 states:

The NSManaged attribute can be used with methods as well as properties, for access to Core Data’s automatically generated Key-Value-Coding-compliant to-many accessors.

@NSManaged var employees: NSSet

@NSManaged func addEmployeesObject(employee: Employee)
@NSManaged func removeEmployeesObject(employee: Employee)
@NSManaged func addEmployees(employees: NSSet)
@NSManaged func removeEmployees(employees: NSSet)

These can be declared in your NSManagedObject subclass. (17583057)

So you just have to declare the following methods and CoreData will take care of the rest:

@NSManaged func addDogBreedsObject(dogBreed: DogBreed)
@NSManaged func removeDogBreedsObject(dogBreed: DogBreed)
@NSManaged func addDogBreeds(dogBreeds: NSSet)
@NSManaged func removeDogBreeds(dogBreeds: NSSet)

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