CoreData和实体关系问题

在我的核心数据模型我有两个实体：CoreData和实体关系问题

InventoryItem
InventoryAction

InventoryItem具有以下属性：
属性：

@property (nonatomic, retain) NSNumber * allowsActions; 
@property (nonatomic, retain) NSNumber * assetID; 
@property (nonatomic, retain) NSNumber * inventoryObjectID; 
@property (nonatomic, retain) NSString * objectDescription; 
@property (nonatomic, retain) NSNumber * quantity; 
@property (nonatomic, retain) NSNumber * retired; 
@property (nonatomic, retain) NSString * serialNumber;

关系：

@property (nonatomic, retain) NSSet *action;

InventoryAction具有以下属性 属性：

@property (nonatomic, retain) NSDate * actionDate; 
@property (nonatomic, retain) NSNumber * actionID; 
@property (nonatomic, retain) NSString * actionLongValue; 
@property (nonatomic, retain) NSString * actionShortValue; 
@property (nonatomic, retain) NSString * notes; 
@property (nonatomic, retain) NSNumber * userActionID; 
@property (nonatomic, retain) NSString * userAuthorizingAction; 
@property (nonatomic, retain) NSString * userPerformingAction; 
@property (nonatomic, retain) NSNumber * userPerformingActionExt; 
@property (nonatomic, retain) NSNumber * inventoryObjectID;

关系

@property (nonatomic, retain) InventoryItem *object;

现在你都在我将告诉你所有存储在CoreData模型中的值都来自JSON格式的Web服务。所有的值都正确存储。

我遇到的问题是，当我从CoreData获取数据时，它只返回唯一的值。

例如：最后InventoryItem具有与之相关6个操作：

“”
“”
“它看起来有点黏糊糊的”
“哦上帝......你为什么要那样做一个无生命的物体，你的病人“，
”它的所有粘糊糊的现在“，
”一切正常”

如1和2具有它只检索值1，3，4，5相同的值，和6

这里是我使用获取数据的代码：

- (void)loadDetails 
{ 
    _fetchRequest = [[NSFetchRequest alloc] init]; 
    _entity = [NSEntityDescription entityForName:@"InventoryObject" inManagedObjectContext:[self managedObjectContext]]; 
    _sort = [NSSortDescriptor sortDescriptorWithKey:@"inventoryObjectID" ascending:YES]; 
    _sortDescriptors = [[NSArray alloc]initWithObjects:_sort, nil]; 

    [_fetchRequest setEntity:_entity]; 
    [_fetchRequest setSortDescriptors:_sortDescriptors]; 

    NSError *error; 
    _fetchedObjects = [[self managedObjectContext] executeFetchRequest:_fetchRequest error:&error]; 
    for (InventoryItem *inventoryItem in _fetchedObjects) { 
     NSLog(@"Object Description: %@", [inventoryItem valueForKey:@"objectDescription"]); 
     NSLog(@"Object ID: %@", [inventoryItem valueForKey:@"inventoryObjectID"]); 
     InventoryAction *action = (InventoryAction *)inventoryItem.action; 
     NSLog(@"Action Long Value: %@", [action valueForKey:@"actionLongValue"]); 
     NSLog(@"Notes: %@", [action valueForKey:@"notes"]); 

    } 
}

这里是JSON回报：

[{"MediaInventoryObjectsId":1,"AssetId":15,"Quantity":1,"SerialNumber":"R45DFL5","Description":"Test Camera 1","AllowActions":true,"Retired":false,"Actions":[{"MediaInventoryActionsId":3,"MediaInventoryObjectsId":1,"UserPerformingActionExt":4444,"UserActionId":1,"ActionDate":"2014-05-19T15:31:45.6","UserPerformingAction":"myersb","UserAuthorizingAction":"mccroskeyl","Notes":null,"ActionShortValue":"OUT","ActionLongValue":"Check Out"},{"MediaInventoryActionsId":4,"MediaInventoryObjectsId":1,"UserPerformingActionExt":4444,"UserActionId":2,"ActionDate":"2014-05-19T15:31:45.6","UserPerformingAction":"myersb","UserAuthorizingAction":"mccroskeyl","Notes":"everything looks good","ActionShortValue":"IN","ActionLongValue":"Check In"}]},{"MediaInventoryObjectsId":2,"AssetId":15,"Quantity":2,"SerialNumber":"IDKMYBFFJILL","Description":"Vanilla Ice Cream","AllowActions":true,"Retired":false,"Actions":[]},{"MediaInventoryObjectsId":3,"AssetId":15,"Quantity":1,"SerialNumber":"R2D23P0","Description":"Droid Bee Box","AllowActions":true,"Retired":false,"Actions":[{"MediaInventoryActionsId":5,"MediaInventoryObjectsId":3,"UserPerformingActionExt":4444,"UserActionId":1,"ActionDate":"2014-05-20T14:48:29.53","UserPerformingAction":"myersb","UserAuthorizingAction":"mccroskeyl","Notes":null,"ActionShortValue":"OUT","ActionLongValue":"Check Out"},{"MediaInventoryActionsId":6,"MediaInventoryObjectsId":3,"UserPerformingActionExt":4444,"UserActionId":2,"ActionDate":"2014-05-20T14:48:29.58","UserPerformingAction":"myersb","UserAuthorizingAction":"mccroskeyl","Notes":"everything looks good","ActionShortValue":"IN","ActionLongValue":"Check In"},{"MediaInventoryActionsId":7,"MediaInventoryObjectsId":3,"UserPerformingActionExt":5555,"UserActionId":1,"ActionDate":"2014-05-20T14:48:29.6","UserPerformingAction":"farmer","UserAuthorizingAction":"mccroskeyl","Notes":null,"ActionShortValue":"OUT","ActionLongValue":"Check Out"},{"MediaInventoryActionsId":8,"MediaInventoryObjectsId":3,"UserPerformingActionExt":5555,"UserActionId":2,"ActionDate":"2014-05-20T14:48:29.6","UserPerformingAction":"farmer","UserAuthorizingAction":"mccroskeyl","Notes":"its all slimy now","ActionShortValue":"IN","ActionLongValue":"Check In"},{"MediaInventoryActionsId":9,"MediaInventoryObjectsId":3,"UserPerformingActionExt":6666,"UserActionId":1,"ActionDate":"2014-05-20T14:48:29.61","UserPerformingAction":"intern1","UserAuthorizingAction":"mccroskeyl","Notes":"it looks kinda slimy","ActionShortValue":"OUT","ActionLongValue":"Check Out"},{"MediaInventoryActionsId":10,"MediaInventoryObjectsId":3,"UserPerformingActionExt":6666,"UserActionId":2,"ActionDate":"2014-05-20T14:48:29.62","UserPerformingAction":"intern1","UserAuthorizingAction":"mccroskeyl","Notes":"oh god....why would you do that to an inanimate object you sicko","ActionShortValue":"IN","ActionLongValue":"Check In"}]}]

任何帮助，您可以提供非常赞赏。我在某处读过NSSet可能只会带回唯一记录。这是真的吗？如果是这样的话，解决方案与关系是什么：行动是NSSet？

谢谢
bnjmnmyers

来源

2014-05-23 bnjmn.myers

你们的关系是声明如下：

@property (nonatomic, retain) NSSet *action;

但你访问它是这样的：

InventoryAction *action = (InventoryAction *)inventoryItem.action;

这是不正确。 action关系是NSSet包含InventoryAction的实例，它不是InventoryAction本身。即使您将此分配给InventoryAction *，但您实际上拥有的是NSSet。然后，你这样做：

NSLog(@"Notes: %@", [action valueForKey:@"notes"]);

如果你在NSSet称之为valueForKey:，它返回键的所有唯一值在一组对象。在这种情况下，它将返回集合中InventoryAction对象的所有notes属性的唯一值，这就是您所看到的。如果你想找到每一个实例，而不是每一个独特的价值，你需要的东西，如：

NSSet *actions = inventoryItem.action; 
for (InventoryAction *action in actions) { 
    NSLog(@"Action note: %@", action.note); 
}

[警告，上面的只是输入到网页浏览器...]

来源

2014-05-23 16:45:38

这做到了。你是男人！谢谢，汤姆！ –

CoreData和实体关系问题

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