有时我在同一个地方有coredata这个错误。有时它确定，在其他时间我有这个错误。这是什么意思？我找不到任何关于它的东西:(
抱歉我的英语:)
conflictList =（NSMergeConflict（0xd447640）for NSManagedObject（0xd41b370）with objectID'0xd41b500'with oldVersion = 4 and newVersion = 5 and old object snapshot = {\ n album = \“{（\ n）} \”; \ n audios = \“{（\ n）} \”; \ n bdate = \“\”; \ n city = \“\”; \ n country = \“\”; \ n dialog = \“{（\ n） } \“; \ n domain = \”white.smoke \“; \ n faculty = 0; \ n facultyName = \”\“; \ n firstName = White; \ n gradu = 0; \ n homePhone = \”\ “; \ n isFriend = 1; \ n isMe = 0; \ n lastName = Smoke; \ n mobilePhone = \”\“; \ n nickName = \”\“; \ n online = 1; \ n photo = \” \ ;; \ n photoBig = \“\”; \ n photoComments = \“{（\ n）} \”; \ n photoMedium = \“\”; \ n photoRec = \“http：//cs10609.vkontakte。 ru / u79185807 / e_8c949409.jpg \“; \ n photos = \”{（\ n（实体：照片; id：0xd482c50;数据：{\ n aid = 121594781; \ n album = nil; \ n comments = \\ “\\”; \ n commentsCount = 0; \ n created = \\“2010-12-10 03:45:01 GMT \\”; \ n owner = \\“0xd41b500 \\”; \ n \\“ owner_id \\“= 79185807; \ n photosNumber = 0; \ n pid = 196997145; \ n src = \\”http://cs10609.vkontakte.ru/u79185807/1215 94781 / m _ \\“; \ n \\”src_big \\“= \\”http：//cs10609.vkontakte.ru/u79185807/121594781/x_ \\“; \ n \\”src_small \\“= \ \“http：//cs10609.vkontakte.ru/u79185807/121594781/s_ \\”; \ n \\“src_xbig \\”= nil; \ n \\“src_xxbig \\”= nil; \ n wallRel = \ \“0xd480840 \\”; \ n}），\ n（实体：照片; id：0xd431570;数据：{\ n aid = 121594781; \ n album = nil; \ n comments = \\“\\”; \ n commentsCount = 0; \ n created = \\“2010-12-10 03:43:01 GMT \\“; \ n owner = \\”0xd41b500 \\“; \ n \\”owner_id \\“= 79185807; \ n photosNumber = 0; \ n pid = 196997029; \ n src = \\”http：/ /cs10609.vkontakte.ru/u79185807/121594781/m_\\";\n \\“src_big \\”= \\“http：//cs10609.vkontakte.ru/u79185807/121594781/x_ \\”; \ n \\“src_small \\”= \\“http：//cs10609.vkontakte.ru/u79185807/121594781/s_ \\”; \ n \\“src_xbig \\”= nil; \ n \\“src_xxbig \\ “= nil; \ n wallRel = \\”0xd42d500 \\“; \ n}）\ n）} \”; \ n rate = \“ - 19 \”; \ n sex = 0; \ nstatuses = \“ {（\ n）} \“; \ n时区= 0; \ n uid = 79185807; \ n university = 0; \ n universityName = \”\“; \ n videos = \”{（\ n）} \“ ; \ n wall = \“{（\ n）} \”; \ n wallPostsCount = 0; \ n wallReplies = \“{（\ n（实体：WallReply; id：0xd448270;数据:) \ n）} \” ; \ n wallSender = \“{（\ n）} \”; \ n}和新缓存的行= {\ n bdate = \“\”; \ n city = \“\”; \ n country = \“\ “; \ n domain = \”white.smoke \“; \ n faculty = 0; \ n facultyName = \”\“; \ n firstName = White; \ n gradua tion = 0; \ n homePhone = \“\”; \ n isFriend = 1; \ n isMe = 0; \ n lastName = Smoke; \ n mobilePhone = \“\”; \ n nickName = \“\”; \ n online = 1; \ n photo = \“\”; \ n photoBig = \“\”; \ n photoMedium = \“\”; \ n photoRec = \“http://cs10609.vkontakte.ru/u79185807/ e_8c949409.jpg \“; \ n rate = \” - 19 \“; \ n sex = 0; \ n timezone = 0; \ n uid = 79185807; \ n university = 0; \ n universityName = \”\“; \ n wallPostsCount = 0; \ n}“）;
当您的数据库从两个不同的位置更改，然后从两个不同的位置保存时，有时会导致合并冲突;在某些情况下，更改可能会影响相同的对象或属性，并且Core Data不会自动覆盖它们，因为这可能会破坏有价值的数据。
有几个选择：
我得到了相同的合并冲突，同时保存了上下文。看到苹果医生here
我使用NSMergePolicy解决了冲突
- (BOOL)resolveConflicts:(NSArray *)list error:(NSError **)error
在创建NSMergePolicy对象时将policyType设置为NSOverwriteMergePolicyType
NSOverwriteMergePolicyType：指定在持久存储中覆盖冲突中已更改对象的状态的策略。
`
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
NSArray * conflictListArray = (NSArray*)[[error userInfo] objectForKey:@"conflictList"];
NSLog(@"conflict array: %@",conflictListArray);
NSError * conflictFixError = nil;
if ([conflictListArray count] > 0) {
NSMergePolicy *mergePolicy = [[NSMergePolicy alloc] initWithMergeType:NSOverwriteMergePolicyType];
if (![mergePolicy resolveConflicts:conflictListArray error:&conflictFixError]) {
NSLog(@"Unresolved conflict error %@, %@", conflictFixError, [conflictFixError userInfo]);
NSLog(@"abort");
abort();
}
} }
简而言之 - 启用合并策略将此添加到您的MOC设置：
客观-C
[_managedObjectContext setMergePolicy:[[NSMergePolicy alloc] initWithMergeType:NSMergeByPropertyObjectTrumpMergePolicyType]];
迅速
lazy var managedObjectContext: NSManagedObjectContext? = {
let coordinator = self.persistentStoreCoordinator
if coordinator == nil {
return nil
}
var managedObjectContext = NSManagedObjectContext()
managedObjectContext.persistentStoreCoordinator = coordinator
//add this line
managedObjectContext.mergePolicy = NSMergePolicy(mergeType: NSMergePolicyType.MergeByPropertyObjectTrumpMergePolicyType);
return managedObjectContext
}()
这可能是半解析，也许:)例如，你有以下代码，它存在于N个对象中（每个对象都在单独的线程中并且在同一时间创建（+ -10ms））：
[coreObject addLinkedObject:linkedObject1];
在上下文中处理例程的时间约为70ms。如果您只是将NSMergePolicy设置为（例如）：NSOverwriteMergePolicy，您将拥有Last-In-Changes：只有最后一个对象将添加链接，因为每个上下文都是持久存储的内存快照。因此，每个快照都是在例程对象创建的时刻创建的。 70ms的处理时间滞后导致coreObject的信息太旧，当你保存它时。换句话说，您将只有一个保存的链接或合并错误。当然，您可以订阅NSManagedObjectContextObjectsDidChangeNotification但在这种情况下您将拥有N！订阅关系或者您可以在主线程中以明星方式跨主要上下文订阅，但有时它不起作用（我使用的是MagicalRecord，版权所有2011 Magical Panda Software LLC。）。我的解决方案是在保存之前重新读取关键coreObject以及使用合适的合并策略：
@synchronized (self) {
if ([context hasChanges]) {
if (needRefresh) {
[context refreshObject:coreObject mergeChanges:NO];
[coreObject addLinkedObject:linkedObject1];
}
NSError *err = nil;
[context save:&err];
if (err) {
NSLog(@"Error Saving Linked Object: %@", [err userInfo]);
[context rollback];
}
}
}
在这种情况下，风险很小。
斯威夫特4
private(set) lazy var mainContext: NSManagedObjectContext = {
let context = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
context.parent = privateContext
context.mergePolicy = NSMergePolicy(merge: .overwriteMergePolicyType)
// Or we can use Trumping
// .mergeByPropertyObjectTrumpMergePolicyType
// .mergeByPropertyStoreTrumpMergePolicyType
// Rolling back is another option
// .rollbackMergePolicyType
return context
}()