如何在Core Data中创建NSManagedObject的深层副本

问题描述

我想在Core Data中复制现有NSManagedObject和相关子对象。我似乎找不到一个简单的方法来做到这一点。

我有一个从Core Data数据库填充的NSArrayController。我想在selectionIndex取对象，并做一个深层副本，保持它相同的父对象和复制所有子对象。

任何帮助是赞赏！ / p>

感谢TechZen的链接。我使用该网站的示例代码并使用这个调用代码：

  RuleSetVersion * object = [[ruleSetVersionArrayController selectedObjects] lastObject]; 
 
 NSString * parentEntity = @RuleSet; 
 
 RuleSetVersion * newObject =（RuleSetVersion *）[self copyObject：object toContext：[self managedObjectContext] parent：parentEntity]; 
 
 [newObject setRuleSetEffectiveDate：[[NSDate alloc] init]]; 
 [newObject setRuleSetVersionLastModifiedDate：[[NSDate alloc] init]]; 
 
 [newObject setRuleSet：object.ruleSet]; 
 
 NSError * error; 
 
 if（[managedObjectContext save：& error] == NO）{
 [NSApp presentError：error]; 
} 
  

解决方案

查看此答案及其连结的范例程式码：

I am trying to make a duplicate of an existing NSManagedObject and related sub-objects in Core Data. I can't seem to find an easy way to do this.

I have an NSArrayController that is populated from a Core Data database. I want to take the object at the selectionIndex and make a deep copy, keeping it related to the same parent object and copying all child objects.

Any assistance is appreciated!

Thanks to TechZen for the link. I used the sample code from that site and used this calling code:

RuleSetVersion *object = [[ruleSetVersionArrayController selectedObjects] lastObject];

NSString *parentEntity = @"RuleSet";

RuleSetVersion *newObject = (RuleSetVersion*)[self copyObject:object toContext:[self managedObjectContext] parent:parentEntity];

[newObject setRuleSetEffectiveDate:[[NSDate alloc] init]];
[newObject setRuleSetVersionLastModifiedDate:[[NSDate alloc] init]];

[newObject setRuleSet:object.ruleSet];

NSError *error;

if ([managedObjectContext save:&error] == NO) {
    [NSApp presentError:error];
}

解决方案

It's fairly involved. See this answer and the sample code linked from it:

How do I copy or move an NSManagedObject from one context to another?

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