iPhone Coredata 错误(NSMergeConflict for NSManagedObject)

Question

有时我在同一位置的 coredata 中会遇到此错误。有时没问题，有时却出现此错误。这是什么意思？我找不到任何相关内容:(

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 graduation = 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 (entity: Photo; id: 0xd482c50 ; data: {\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/u79185807/121594781/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 = \\"0xd480840 \\";\n}),\n (entity: Photo; id: 0xd431570 ; data: {\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;\n statuses = \"{(\n)}\";\n timezone = 0;\n uid = 79185807;\n university = 0;\n universityName = \"\";\n videos = \"{(\n)}\";\n wall = \"{(\n)}\";\n wallPostsCount = 0;\n wallReplies = \"{(\n (entity: WallReply; id: 0xd448270 ; data: )\n)}\";\n wallSender = \"{(\n)}\";\n} and new cached row = {\n bdate = \"\";\n city = \"\";\n country = \"\";\n domain = \"white.smoke\";\n faculty = 0;\n facultyName = \"\";\n firstName = White;\n graduation = 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}" );

Answer 1

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，而 Core Data 不会自动覆盖它们，因为这可能会破坏有值(value)的数据。

有几个选项:

• 当您遇到合并冲突时，请迭代其信息，并根据应用程序的需要手动解决所有冲突。
• Set the merge policy托管对象上下文的一个或多个将自动解决某些类型的冲突。有些合并政策具有部分破坏性，有些则具有很强的破坏性 - 哪一种是正确的实际上取决于您的应用程序以及所保存数据的重要性。
• 使用mergeChangesFromContextDidSaveNotification:快速而紧密地将更改集成到尚未保存的托管对象上下文中。请注意，这可能仍需要一定程度的冲突解决，但应有助于最大程度地降低严重性。