关于核心数据版本迁移的“无法两次添加相同的存储”

Question

我正试图在CoreData的两个版本之间进行迁移，这些迁移基本上与新版本具有两种配置的事实有所不同，因此我可以将实体保存在两个不同的sqlite文件（一个只读在主包中，一个是旧的sqlite，现在只用于用户数据）。我还添加了一个模型映射来映射差异，特别是重置由于多个配置而丢失的实体之间的关系。 如果从头开始安装，并且应用程序文档目录中的用户数据sqlite中插入新记录，应用程序将正常运行而不会崩溃。 问题是，当我试图从以前的核心数据版本迁移：在应用程序启动时不崩溃，但在第一次executeFetchRequest它在coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: "Userdata", URL: urlUser, options: optionsUser, error: &errorUser)（含调试观看）和控制台回报崩溃此日志：

2015-02-23 18:48:24.052 MedAbility[21480:585606] CoreData: error: -addPersistentStoreWithType:SQLite configuration:(null) URL:file:///Volumes/Documenti/Users/andrea/Library/Developer/CoreSimulator/Devices/301801BE-4B6A-4371-BE66-3E71557B0897/data/Containers/Data/Application/FBEC0124-1D74-4F94-99F2-6F492281AA8E/Documents/MedAbility.sqlite options:{ NSInferMappingModelAutomaticallyOption = 1; NSMigratePersistentStoresAutomaticallyOption = 1; } ... returned error Error Domain=NSCocoaErrorDomain Code=134080 "The operation couldn’t be completed. (Cocoa error 134080.)" UserInfo=0x7fb50ae481d0 {NSUnderlyingException=Can't add the same store twice} with userInfo dictionary { NSUnderlyingException = "Can't add the same store twice"; } 2015-02-23 18:48:24.061 MedAbility[21480:585606] CoreData: error: -addPersistentStoreWithType:SQLite configuration:Userdata URL:file:///Volumes/Documenti/Users/andrea/Library/Developer/CoreSimulator/Devices/301801BE-4B6A-4371-BE66-3E71557B0897/data/Containers/Data/Application/FBEC0124-1D74-4F94-99F2-6F492281AA8E/Documents/MedAbility.sqlite options:{ NSInferMappingModelAutomaticallyOption = 1; NSMigratePersistentStoresAutomaticallyOption = 1; } ... returned error Error Domain=NSCocoaErrorDomain Code=134080 "The operation couldn’t be completed. (Cocoa error 134080.)" UserInfo=0x7fb50ae481d0 {NSUnderlyingException=Can't add the same store twice} with userInfo dictionary { NSUnderlyingException = "Can't add the same store twice"; }

这是我的代码：

旧版本PersistentStoreCoordinator：

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = { 
     // Create the coordinator and store 
     var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel) 
     let url = self.applicationDocumentsDirectory.URLByAppendingPathComponent("MedAbility.sqlite") 
     var error: NSError? = nil 
     var failureReason = "There was an error creating or loading the application's saved data." 
     // Set options for migrations 
     let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true] 
     if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: nil, URL: url, options: options, error: &error) == nil { 
      coordinator = nil 
      // Report any error we got. 
      let dict = NSMutableDictionary() 
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" 
      dict[NSLocalizedFailureReasonErrorKey] = failureReason 
      dict[NSUnderlyingErrorKey] = error 
      error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict) 

      NSLog("Unresolved error \(error), \(error!.userInfo)") 
     } 

     // Exclude db from backup 
     Util.addSkipBackupAttributeToItemAtURL(url) 

     return coordinator 
     }() 

新版本PersistentStoreCoordinator：

lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator? = { 
     // The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail. 
     // Create the coordinator and store 
     var coordinator: NSPersistentStoreCoordinator? = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel) 

     let url = NSBundle.mainBundle().URLForResource("MedAbilityDomande", withExtension: "sqlite") 
     var error: NSError? = nil 
     var failureReason = "There was an error creating or loading the application's saved data." 
     // Set questions sqlite as read-only 
     let options = [NSReadOnlyPersistentStoreOption: true] 
     if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: "Domande", URL: url, options: options, error: &error) == nil { 
      coordinator = nil 
      // Report any error we got. 
      let dict = NSMutableDictionary() 
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" 
      dict[NSLocalizedFailureReasonErrorKey] = failureReason 
      dict[NSUnderlyingErrorKey] = error 
      error = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict) 

      NSLog("Unresolved error \(error), \(error!.userInfo)") 
     } 

     let urlUser = self.applicationDocumentsDirectory.URLByAppendingPathComponent("MedAbility.sqlite") 
     var errorUser: NSError? = nil 
     var failureReasonUser = "There was an error creating or loading the application's saved data." 
     // Set migration options 
     let optionsUser = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true] 
     if coordinator!.addPersistentStoreWithType(NSSQLiteStoreType, configuration: "Userdata", URL: urlUser, options: optionsUser, error: &errorUser) == nil { 
      coordinator = nil 
      // Report any error we got. 
      let dict = NSMutableDictionary() 
      dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" 
      dict[NSLocalizedFailureReasonErrorKey] = failureReasonUser 
      dict[NSUnderlyingErrorKey] = errorUser 
      errorUser = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict) 

      NSLog("Unresolved error \(errorUser), \(errorUser!.userInfo)") 
     } 

     return coordinator 
     }() 

有人知道我该如何解决这个问题？

感谢您的帮助！

编辑

我做了一些测试，我发现第一个数据库的评论coordinator!.addPersistentStoreWithType (NSSQLiteStoreType, configuration: "Questions", URL: url, options: options, error: & error)，应用程序启动时没有问题，显然没有没有加入数据库的内容。如果我反向添加两个数据库，那么应用程序会崩溃，除了在“ex-first now-second”数据库（“MedAbilityDomande.sqlite”）上调用的“URL：file：[...]在实践中，它是增加了第二个数据库的问题，而不是一个特定的数据库。看起来，将旧数据库迁移到用于用户数据的新数据库实际上不会迁移配置，因此仍然是旧配置，它将实体与插入到mainBundle中的新只读数据库重叠。正如我之前所说的，如果应用程序从头开始（没有迁移），完美地工作。

你有什么想法吗？

非常感谢你！

Answer 1

我终于找到了解决方案！我基于数据库创建了数据库MedAbilityDomande.sqlite，该数据库在我想迁移以用于用户数据之后。这带来了两个数据库具有相同的UUID，从而产生错误"Can't add the same store twice"。只需更改应用程序包（MedAbilityDomande.sqlite）中数据库的UUID即可，而且一切运行良好。

直到下一次！