blocks|key|433231|text|是的，这将不再有效，Swift无法在运行时生成访问器，这样会破坏类型系统。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|433232|您需要做的是使用关键路径：|433233|var+manyRelation+=+myObject.valueForKeyPath("subObjects")+as+NSMutableSet
manyRelation.addObject(subObject)
/*+(Not+tested)+*/|code-block|syntax|javascript|433234|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Yeah that's not going to work anymore, Swift cannot generate accessors at runtime in this way, it would break the type system.

What you have to do is use the key paths:

<pre><code>var manyRelation = myObject.valueForKeyPath("subObjects") as NSMutableSet
manyRelation.addObject(subObject)
/* (Not tested) */
</code></pre>

blocks|key|433287|text|假设您有以下实体：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|433288|人物|unordered-list-item|433289|角色|433290|部门|433291|在您的Person实体中，它们与Role和Department有着非常多的关系。您的托管对象可能如下所示：|offset|length|style|CODE|433292|class+Person+:+NSManagedObject
{
++++@NSManaged+var+roles+:+Array<Role>
++++@NSManaged+var+department+:+Department
}|code-block|syntax|javascript|433293|与逆的关系(它们都应该有)只需要为要建立的链接设置一方。|433294|例如，如果将Person的department属性设置为Department对象，则反向Department.people属性现在也将包含此Person对象。|433295|entityMap^0|0|0|0|0|3|6|G|4|L|A|0|0|0|6|6|D|A|S|A|18|H|1Y|6|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|10|8|@]|9|@]|A|$]]|$1|E|3|F|5|D|7|11|8|@]|9|@]|A|$]]|$1|G|3|H|5|D|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|13|8|@$K|14|L|15|M|N]|$K|16|L|17|M|N]|$K|18|L|19|M|N]]|9|@]|A|$]]|$1|O|3|P|5|Q|7|1A|8|@]|9|@]|A|$R|S]]|$1|T|3|U|5|6|7|1B|8|@]|9|@]|A|$]]|$1|V|3|W|5|6|7|1C|8|@$K|1D|L|1E|M|N]|$K|1F|L|1G|M|N]|$K|1H|L|1I|M|N]|$K|1J|L|1K|M|N]|$K|1L|L|1M|M|N]]|9|@]|A|$]]|$1|X|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]]|Y|$]]

Let's say you have the following entities:

<ul>
<li>Person</li>
<li>Role</li>
<li>Department</li>
</ul>

In your <code>Person</code> entity, they have a to-many relationship with <code>Role</code> and to-one with <code>Department</code>. Your managed object might look something like this:

<pre><code>class Person : NSManagedObject
{
 @NSManaged var roles : Array&lt;Role&gt;
 @NSManaged var department : Department
}
</code></pre>

Relationships with inverses (all should have them) only require one side to be set for the link to be established. 

For example, if you set a <code>Person</code>'s <code>department</code> property to a <code>Department</code> object, the inverse <code>Department.people</code> property would now also have this <code>Person</code> object contained inside.

blocks|key|433355|text|目标C中的核心数据自动创建setter方法(1)：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|433356|默认情况下，Core数据动态地为托管对象类的建模属性(属性和关系)创建高效的公共和原始获取和设置访问器方法。这包括键值编码可变代理方法，如addObject:和removes:，如mutableSetValueForKey：-托管对象的文档中详细介绍的那样，托管对象实际上是所有到多个关系的可变代理。|blockquote|433357|就目前Xcode6-Beta2中的Swift而言，您必须自己实现这些访问器。例如，如果您有一个无序到多个关系，从Way到Node，您可以这样实现addNodesObject：|style|CODE|433358|class+Way+:+NSManagedObject+{
++++@NSManaged+var+nodes+:+NSSet

++++func+addNodesObject(value:+Node)+{
++++++++self.mutableSetValueForKey("nodes").addObject(value)
++++}
}|code-block|syntax|javascript|433359|这里的关键是您必须使用mutableSetValueForKey+/+mutableOrderedSetValueForKey+/+mutableArrayValueForKey。在这些集合/数组上，您可以调用addObject，它们将存储在下一次刷新中。|433360|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreData/Articles/cdAccessorMethods.html#//apple_ref/doc/uid/TP40002154-SW9^0|M|1|0|0|0|1K|3|1O|4|20|E|0|0|B|L|Z|S|1U|N|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|F|7|13|8|@]|9|@]|C|$]]|$1|G|3|H|5|6|7|14|8|@$A|15|B|16|I|J]|$A|17|B|18|I|J]|$A|19|B|1A|I|J]]|9|@]|C|$]]|$1|K|3|L|5|M|7|1B|8|@]|9|@]|C|$N|O]]|$1|P|3|Q|5|6|7|1C|8|@$A|1D|B|1E|I|J]|$A|1F|B|1G|I|J]|$A|1H|B|1I|I|J]]|9|@]|C|$]]|$1|R|3|-4|5|6|7|1J|8|@]|9|@]|C|$]]]|S|$T|$5|U|V|W|C|$X|Y]]]]

Core Data in Objective C automatically creates setter methods (<a href="https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreData/Articles/cdAccessorMethods.html#//apple_ref/doc/uid/TP40002154-SW9">1</a>):

<blockquote>
 By default, Core Data dynamically creates efficient public and primitive get and set accessor methods for modeled properties (attributes and relationships) of managed object classes. This includes the key-value coding mutable proxy methods such as addObject: and removes:, as detailed in the documentation for mutableSetValueForKey:—managed objects are effectively mutable proxies for all their to-many relationships.
</blockquote>

As things currently stand with Swift in Xcode6-Beta2, you'd have to implement those accessors yourself. For example if you have an unordered to-many relationship, from <code>Way</code> to <code>Node</code>, you'd implement <code>addNodesObject</code> like this:

<pre><code>class Way : NSManagedObject {
 @NSManaged var nodes : NSSet

 func addNodesObject(value: Node) {
 self.mutableSetValueForKey("nodes").addObject(value)
 }
}
</code></pre>

Key here is that you'd have to use <code>mutableSetValueForKey</code> / <code>mutableOrderedSetValueForKey</code> / <code>mutableArrayValueForKey</code>. On these sets / arrays, you can call addObject and they'll be stored on the next flush.

blocks|key|52028|text|在上面的解决方案上扩展一个到多个关系是NSMutableSet，因此这允许您直接向角色添加或删除Person+NSManagedObject，在这种情况下，一个人有一个角色，角色有多个人。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|52029|我已经测试了这个解决方案在Xcode+Beta-3和这工作！|52030|该代码使该部简化显示从一个人访问角色和从一个角色访问人员所需的一对一和多个代码。|52031|import+CoreData


@objc(Person)+class+Person:+NSManagedObject+{

++++@NSManaged+var+name:+String

++++//One+to+One+relationship+in+your+Model
++++@NSManaged+var+roles:+Roles

}


@objc(Roles)+class+Roles:+NSManagedObject+{

++++@NSManaged+var+role:+String

++++//One+to+Many+relationship+in+your+Model
++++@NSManaged+var+persons:+NSMutableSet

}

extension+Roles+{

++++func+addPersonsObject(value:+Person)+{
++++++++self.persons.addObject(value)
++++}

++++func+removePersonsObject(value:+Person)+{
++++++++self.persons.removeObject(value)
++++}

++++func+addPersons(values:+[Person])+{
++++++++self.persons.addObjectsFromArray(values)
++++}

++++func+removePersons(values:+[Person])+{
++++++++for+person+in+values+as+[Person]+{
++++++++++++self.removePersonsObject(person)
++++++++}
++++}

}|code-block|syntax|javascript|52032|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Expanding on the solution above one to many relationships are NSMutableSet so this allows you to directly add or remove the Person NSManagedObject to the Roles in this case a Person has one Role and Roles have many Person(s)

I have tested this solution under Xcode Beta-3 and this works!

This code takes out the Department to simplify showing the one to one and one to many code required to access Roles from a Person and Persons from a Role.

<pre><code>import CoreData


@objc(Person) class Person: NSManagedObject {

 @NSManaged var name: String

 //One to One relationship in your Model
 @NSManaged var roles: Roles

}


@objc(Roles) class Roles: NSManagedObject {

 @NSManaged var role: String

 //One to Many relationship in your Model
 @NSManaged var persons: NSMutableSet

}

extension Roles {

 func addPersonsObject(value: Person) {
 self.persons.addObject(value)
 }

 func removePersonsObject(value: Person) {
 self.persons.removeObject(value)
 }

 func addPersons(values: [Person]) {
 self.persons.addObjectsFromArray(values)
 }

 func removePersons(values: [Person]) {
 for person in values as [Person] {
 self.removePersonsObject(person)
 }
 }

}
</code></pre>

blocks|key|433433|text|从Xcode+7和SWIFT2.0(参见新闻稿#17583057)开始，您只需将以下定义添加到生成的扩展名文件中：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|433434|extension+PersonModel+{
++++//+This+is+what+got+generated+by+core+data
++++@NSManaged+var+name:+String?
++++@NSManaged+var+hairColor:+NSNumber?
++++@NSManaged+var+parents:+NSSet?

++++//+This+is+what+I+manually+added
++++@NSManaged+func+addParentsObject(value:+ParentModel)
++++@NSManaged+func+removeParentsObject(value:+ParentModel)
++++@NSManaged+func+addParents(value:+Set<ParentModel>)
++++@NSManaged+func+removeParents(value:+Set<ParentModel>)
}|code-block|syntax|javascript|433435|这起作用是因为|433436|NSManaged属性可以与方法和属性一起使用，用于访问符合-许多访问器的核心数据的自动生成的密钥值编码。|blockquote|433437|添加此定义将允许您向集合中添加项。不知道为什么这些不是自动生成的..。|433438|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/prerelease/tvos/releasenotes/DeveloperTools/RN-Xcode/Chapters/xc7_release_notes.html^0|K|C|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@$A|Y|B|Z|1|10]]|C|$]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|12|8|@]|9|@]|C|$]]|$1|K|3|L|5|M|7|13|8|@]|9|@]|C|$]]|$1|N|3|O|5|6|7|14|8|@]|9|@]|C|$]]|$1|P|3|-4|5|6|7|15|8|@]|9|@]|C|$]]]|Q|$R|$5|S|T|U|C|$V|W]]]]

As of Xcode 7 and Swift 2.0 (see <a href="https://developer.apple.com/library/prerelease/tvos/releasenotes/DeveloperTools/RN-Xcode/Chapters/xc7_release_notes.html" rel="nofollow noreferrer">release note #17583057</a>), you are able to just add the following definitions to the generated extension file:

<pre><code>extension PersonModel {
 // This is what got generated by core data
 @NSManaged var name: String?
 @NSManaged var hairColor: NSNumber?
 @NSManaged var parents: NSSet?

 // This is what I manually added
 @NSManaged func addParentsObject(value: ParentModel)
 @NSManaged func removeParentsObject(value: ParentModel)
 @NSManaged func addParents(value: Set&lt;ParentModel&gt;)
 @NSManaged func removeParents(value: Set&lt;ParentModel&gt;)
}
</code></pre>

This works because 

<blockquote>
 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.
</blockquote>

Adding this definition will allow you to add items to your collections. Not sure why these aren't just generated automatically...

blocks|key|2041360|text|您只需使用类型化的Set就可以了，这要容易得多。按照前面的答案中的@Nycen和@lehn0058提供的示例，您只需写：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2041361|extension+PersonModel+{
++++@NSManaged+var+parents:+Set<ParentModel>?
}|code-block|syntax|javascript|2041362|然后使用insert和remove方法的Set。|2041363|entityMap^0|9|3|0|0|4|6|B|6|K|3|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|N|$]]

You can just use a typed <code>Set</code> instead which is far easier. Following the example provided by @Nycen and @lehn0058 in the previous answer, you can just write:

<pre><code>extension PersonModel {
 @NSManaged var parents: Set&lt;ParentModel&gt;?
}
</code></pre>

And then use the <code>insert</code> and <code>remove</code> methods of the <code>Set</code>.

blocks|key|2041400|text|由于您现在只需要为两种关系设置关系的一方，所以如果您有一个1<->多个关系，例如Department对象有多个Person对象，那么您只需使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2041401|aPerson.department+=+aDepartment|code-block|syntax|javascript|2041402|如果您检查一下，您会发现aDepartment.people+(假设这是您所建立的互惠关系)现在将包含'aPerson‘Person对象。|2041403|如果这种关系是多<->多的，那么上面的一个更复杂的解决方案就显得必要了。|2041404|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

As you only need to set one side of a relationship for both to be set nowadays, it's particularly simple if you have a 1&lt;->many relationship, e.g. a Department object has multiple Person objects, then you can just use:

<pre><code>aPerson.department = aDepartment
</code></pre>

If you check you'll find that aDepartment.people (assuming that is the reciprocal relationship you've set up) will now contain the 'aPerson' Person object.

If the relationship is many&lt;->many then one of the more complex solutions above appears necessary.

blocks|key|2041431|text|从Xcode+8和Swift+3.0开始，Xcode现在为关系生成访问器。例如，我有一个NSManagedObject类商店，它与条目有一对多的关系；我称之为关系SellsItems。生成的Store类现在具有以下从SellsItems中添加和删除的扩展。向关系中添加或删除项就像调用这些函数一样简单。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2041432|//+MARK:+Generated+accessors+for+sellsItems
extension+Store+{
++++@objc(addSellsItemsObject:)
++++@NSManaged+public+func+addToSellsItems(_+value:+Item)

++++@objc(removeSellsItemsObject:)
++++@NSManaged+public+func+removeFromSellsItems(_+value:+Item)

++++@objc(addSellsItems:)
++++@NSManaged+public+func+addToSellsItems(_+values:+NSSet)

++++@objc(removeSellsItems:)
++++@NSManaged+public+func+removeFromSellsItems(_+values:+NSSet)
}|code-block|syntax|javascript|2041433|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

As of Xcode 8 and Swift 3.0, Xcode now generates accessors for relationships. For example, I have an NSManagedObject class Store, that has a one to many relationship with Items; I've called that relationship SellsItems. The generated class for Store now has the following extension to add and remove from SellsItems. Adding or removing items to the relationship is as simple as calling these functions. 

<pre><code>// MARK: Generated accessors for sellsItems
extension Store {
 @objc(addSellsItemsObject:)
 @NSManaged public func addToSellsItems(_ value: Item)

 @objc(removeSellsItemsObject:)
 @NSManaged public func removeFromSellsItems(_ value: Item)

 @objc(addSellsItems:)
 @NSManaged public func addToSellsItems(_ values: NSSet)

 @objc(removeSellsItems:)
 @NSManaged public func removeFromSellsItems(_ values: NSSet)
}
</code></pre>

How does one add an object to a relationship property in an <code>NSManagedObject</code> subclass in Swift?

In Objective-C, when you generate an <code>NSManagedObject</code> subclass in Xcode from the data model, there's an automatically generated class extension which contains declarations like:

<pre><code>@interface MyManagedObject (CoreDataGeneratedAccessors)

 - (void)addMySubObject: (MyRelationshipObject *)value;
 - (void)addMySubObjects: (NSSet *)values;

@end
</code></pre>

However Xcode currently lacks this class generation capability for Swift classes. 

If I try and call equivalent methods directly on the Swift object:

<pre><code>myObject.addSubObject(subObject)
</code></pre>

...I get a compiler error on the method call, because these generated accessors are not visible.

I've declared the relationship property as <code>@NSManaged</code>, as described in the documentation.

Or do I have to revert to Objective-C objects for data models with relationships?

Setting an NSManagedObject relationship in Swift

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

如何在Swift中的NSManagedObject子类中向关系属性添加对象？在Objective中，当从数据模型在Xcode中生成NSManagedObject子类时，有一个自动生成的类扩展，其中包含如下声明：@interface MyManagedObject (CoreDataGeneratedAccessors)...

问在Swift中设置NSManagedObject关系
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在Swift中设置NSManagedObject关系EN