core-data - 核心数据关系导致删除后保存错误

Question

这个问题可能是一个不太可能的问题。当我删除实体后保存时，我无法找出核心数据项目中出现的错误。

我有两个主要的工作实体:一套服装和一篇文章。我可以毫无问题地创建它们，但是当我删除它们时，我收到以下错误日志:

对于服装:

2009-09-22 20:17:37.771 itryiton[29027:20b] Operation could not be completed. (Cocoa error 1600.)
2009-09-22 20:17:37.773 itryiton[29027:20b]   {
    NSLocalizedDescription = "Operation could not be completed. (Cocoa error 1600.)";
    NSValidationErrorKey = outfitArticleViewProperties;
    NSValidationErrorObject = <Article: 0x12aa3c0> (entity: Article; id: 0x12b49a0 <x-coredata://7046DA47-FCE1-4E21-8D7B-E532AAC0CC46/Article/p1> ; data: {
    articleID = 2009-09-22 19:05:19 -0400;
    articleImage = 0x12b4de0 <x-coredata://7046DA47-FCE1-4E21-8D7B-E532AAC0CC46/ArticleImage/p1>;
    articleType = nil;
    attributeTitles = "(...not nil..)";
    color = nil;
    comment = nil;
    dateCreated = 2009-09-22 19:05:19 -0400;
    designer = nil;
    imageView = "(...not nil..)";
    location = "(...not nil..)";
    outfitArticleViewProperties =     (
        0x12b50f0 <x-coredata://7046DA47-FCE1-4E21-8D7B-E532AAC0CC46/OutfitArticleViewProperties/p1>
    );
    ownesOrWants = 0;
    pattern = nil;
    price = nil;
    retailer = nil;
    thumbnail = "(...not nil..)";
    washRequirements = nil;
    wearableSeasons = nil;
});
    NSValidationErrorValue =     {(
        <OutfitArticleViewProperties: 0x1215340> (entity: OutfitArticleViewProperties; id: 0x12b50f0 <x-coredata://7046DA47-FCE1-4E21-8D7B-E532AAC0CC46/OutfitArticleViewProperties/p1> ; data: {
    article = 0x12b49a0 <x-coredata://7046DA47-FCE1-4E21-8D7B-E532AAC0CC46/Article/p1>;
    articleViewPropertiesID = nil;
    outfit = nil;
    touch = nil;
    view = "(...not nil..)";
})
    )};
}

如果我删除一篇文章，我会得到:

2009-09-22 18:58:38.591 itryiton[28655:20b] Operation could not be completed. (Cocoa error 1560.)
2009-09-22 18:58:38.593 itryiton[28655:20b]   DetailedError: {
    NSLocalizedDescription = "Operation could not be completed. (Cocoa error 1600.)";
    NSValidationErrorKey = articleImage;
    NSValidationErrorObject = <Article: 0x12aa340> (entity: Article; id: 0x12b3f10 <x-coredata://05340FA6-B5DC-4646-A5B4-745C828C73C3/Article/p1> ; data: {
    articleID = 2009-09-22 18:58:26 -0400;
    articleImage = 0x12b4d00 <x-coredata://05340FA6-B5DC-4646-A5B4-745C828C73C3/ArticleImage/p1>;
    articleType = nil;
    attributeTitles = "(...not nil..)";
    color = nil;
    comment = nil;
    dateCreated = 2009-09-22 18:58:26 -0400;
    designer = nil;
    imageView = "(...not nil..)";
    location = "(...not nil..)";
    outfitArticleViewProperties =     (
        0x12b5010 <x-coredata://05340FA6-B5DC-4646-A5B4-745C828C73C3/OutfitArticleViewProperties/p1>
    );
    ownesOrWants = 0;
    pattern = nil;
    price = nil;
    retailer = nil;
    thumbnail = "(...not nil..)";
    washRequirements = nil;
    wearableSeasons = nil;
});
    NSValidationErrorValue = <ArticleImage: 0x12ad600> (entity: ArticleImage; id: 0x12b4d00 <x-coredata://05340FA6-B5DC-4646-A5B4-745C828C73C3/ArticleImage/p1> ; data: {
    article = 0x12b3f10 <x-coredata://05340FA6-B5DC-4646-A5B4-745C828C73C3/Article/p1>;
    image = "(...not nil..)";
});
}

1600 错误是:

NSValidationRelationshipDeniedDeleteError
Error code to denote some relationship
with delete rule NSDeleteRuleDeny is
non-empty.

Available in Mac OS X v10.4 and later.

Declared in CoreDataErrors.h.

但我一生都看不出哪种关系会阻止删除。如果某个核心数据向导能够看到我的方法的错误，我会感到谦卑。

我无法将此标记为已解决，因为我没有真正解决它，但我确实有一个可行的解决方法。在每个 managedObjects 的 .m 中，我添加了一个如下所示的方法:

-(void) deleteFromManangedObjectContext{ 
   self.outfit = nil; 
   self.article = nil; 
   [[self managedObjectContext] deleteObject:self]; 
} 

所以你可以看到，首先我手动清除关系，然后让对象删除自身。在其他对象中，我的删除方法不是nil-ing，而是在某些对象关系上调用，以获得级联。

Answer 1

我刚刚遇到删除失败的问题，并想到了这个问题。我已经弄清楚了我的问题，并认为我也会分享这个问题，也许有人也会遇到同样的问题。

我犯的错误是，我尝试删除的对象 (A) 与另一个对象 (B) 有关系，删除规则为 NULL。但是，对象 B 也与 A 存在关系，并且该关系是非可选的。因此，当我删除A时，B与A的关系变为空，这是不允许的。当我将删除规则更改为级联时，它起作用了。