ios - 当关系从多变为一时如何执行迁移？

Question

这是我在 Business 实体的源模型中所拥有的:

这就是我在 Business 实体的目标模型中所拥有的:

如您所见，我将关系从多更改为一，从 users 更改为 user。

但现在我有以下错误:

URL:file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/POSowner.sqlite options:{    NSInferMappingModelAutomaticallyOption = 1;    NSMigratePersistentStoresAutomaticallyOption = 1;} ... returned error Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={sourceURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/POSowner.sqlite, reason=Cannot migrate store in-place: Validation error missing attribute values on mandatory destination relationship, destinationURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/.POSowner.sqlite.migrationdestination_41b5a6b5c6e848c462a8480cd24caef3, NSUnderlyingError=0x170458990 {Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={entity=Business, attribute=user, reason=Validation error missing attribute values on mandatory destination relationship}}} with userInfo dictionary {    NSUnderlyingError = "Error Domain=NSCocoaErrorDomain Code=134110 \"An error occurred during persistent store migration.\" UserInfo={entity=Business, attribute=user, reason=Validation error missing attribute values on mandatory destination relationship}";    destinationURL = "file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/.POSowner.sqlite.migrationdestination_41b5a6b5c6e848c462a8480cd24caef3";    reason = "Cannot migrate store in-place: Validation error missing attribute values on mandatory destination relationship";    sourceURL = "file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/POSowner.sqlite";}fatal error: 'try!' expression unexpectedly raised an error: Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={sourceURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/POSowner.sqlite, reason=Cannot migrate store in-place: Validation error missing attribute values on mandatory destination relationship, destinationURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/.POSowner.sqlite.migrationdestination_41b5a6b5c6e848c462a8480cd24caef3, NSUnderlyingError=0x170458990 {Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={entity=Business, attribute=user, reason=Validation error missing attribute values on mandatory destination relationship}}}: file /Library/Caches/com.apple.xbs/Sources/swiftlang/swiftlang-800.0.58.6/src/swift/stdlib/public/core/ErrorType.swift, line 1782016-11-30 14:25:43.070185 POSowner[3474:513840] fatal error: 'try!' expression unexpectedly raised an error: Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={sourceURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/POSowner.sqlite, reason=Cannot migrate store in-place: Validation error missing attribute values on mandatory destination relationship, destinationURL=file:///private/var/mobile/Containers/Shared/AppGroup/00C2A6C6-8149-4CF7-95E1-6ABD8A2B3B57/.POSowner.sqlite.migrationdestination_41b5a6b5c6e848c462a8480cd24caef3, NSUnderlyingError=0x170458990 {Error Domain=NSCocoaErrorDomain Code=134110 "An error occurred during persistent store migration." UserInfo={entity=Business, attribute=user, reason=Validation error missing attribute values on mandatory destination relationship}}}: file /Library/Caches/com.apple.xbs/Sources/swiftlang/swiftlang-800.0.58.6/src/swift/stdlib/public/core/ErrorType.swift, line 178

而且我不知道该怎么做才能解决这个问题。有什么想法吗？

这就是我设置核心数据堆栈的方式:

static func mr_setupCoreDataStack() {    guard NSPersistentStoreCoordinator.mr_default() == nil else {        return    }    let managedObjectModel = NSManagedObjectModel.mr_default()    let persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel!)    var storePath = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: SharedGroupName)    storePath = storePath!.appendingPathComponent("POSowner.sqlite")    let options = [NSMigratePersistentStoresAutomaticallyOption: true, NSInferMappingModelAutomaticallyOption: true]    try! persistentStoreCoordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: storePath, options: options)    NSPersistentStoreCoordinator.mr_setDefaultStoreCoordinator(persistentStoreCoordinator)    NSManagedObjectContext.mr_initializeDefaultContext(with: persistentStoreCoordinator)}

Answer 1

最简单的解决方案是删除当前数据库并允许 MagicalRecord 创建一个新数据库而不进行任何迁移。请记住只一次。

static func mr_setupCoreDataStack() {

    var storePath = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: SharedGroupName)
    storePath = storePath!.appendingPathComponent("POSowner.sqlite")
    try! FileManager.default.removeItem(at: storePath!)

}