Iphone CoreData版本控制和阻止轻量级迁移
我已经启用了核心数据模型的版本控制，并且一直在使用轻量级迁移。我的代码总是尝试进行轻量级迁移，如果因为模型不兼容而失败，它会返回到删除所有现有数据并从服务器重新蚀刻。 因此，轻量级迁移只是为了提高效率，而不是为了正确性 我现在想做的是修改我的模型，理论上轻量级迁移可以处理，但实际上我需要从服务器获取新数据。我想以某种方式标记模型，而不是通过轻量级迁移进行升级。例如，如果某个字段名没有更改，但该字段的含义已更改，以致旧代码与新代码库不兼容。（这只是一个例子。）Iphone CoreData版本控制和阻止轻量级迁移,iphone,ios,cocoa-touch,core-data,core-data-migration,Iphone,Ios,Cocoa Touch,Core Data,Core Data Migration,我已经启用了核心数据模型的版本控制，并且一直在使用轻量级迁移。我的代码总是尝试进行轻量级迁移，如果因为模型不兼容而失败，它会返回到删除所有现有数据并从服务器重新蚀刻。 因此，轻量级迁移只是为了提高效率，而不是为了正确性 我现在想做的是修改我的模型，理论上轻量级迁移可以处理，但实际上我需要从服务器获取新数据。我想以某种方式标记模型，而不是通过轻量级迁移进行升级。例如，如果某个字段名没有更改，但该字段的含义已更改，以致旧代码与新代码库不兼容。（这只是一个例子。） 有没有人找到一种方法将两个模型标记为
有没有人找到一种方法将两个模型标记为不兼容，这样轻量级迁移就不会升级它们？我以前也遇到过同样的问题 我有一种方法，可以尝试使用映射模型来迁移数据，如果要关闭轻量级迁移，应该使用映射模型 如果您不打算进行大量的数据映射，xcode将自动创建一个映射模型，该模型的工作方式与轻量级迁移完全相同。每次向核心数据添加新版本时，只需创建一个新的“映射模型”文件。只需进入“文件->新建->新建文件”，在核心数据下应该有一个映射模型模板。选择它并选择源和目标版本 我没有在github上公开我的代码，所以我只在这里发布迁移方法
- (BOOL)progressivelyMigrateURL:(NSURL*)sourceStoreURL ofType:(NSString*)type toModel:(NSManagedObjectModel*)finalModel
{
NSError *error = nil;
// if store dosen't exist skip migration
NSString *documentDir = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
if(![NSBundle pathForResource:@"YongoPal" ofType:@"sqlite" inDirectory:documentDir])
{
migrationProgress = 1.0;
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
// remove migration view
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:[NSNumber numberWithBool:YES] waitUntilDone:YES];
[self.migrationView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
self.migrationView = nil;
self.migrationProgressLabel = nil;
self.migrationProgressView = nil;
self.migrationSpinner = nil;
return YES;
}
//START:progressivelyMigrateURLHappyCheck
NSDictionary *sourceMetadata = [NSPersistentStoreCoordinator metadataForPersistentStoreOfType:type URL:sourceStoreURL error:&error];
if (!sourceMetadata)
{
return NO;
}
if ([finalModel isConfiguration:nil compatibleWithStoreMetadata:sourceMetadata])
{
migrationProgress = 1.0;
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
// remove migration view
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:[NSNumber numberWithBool:YES] waitUntilDone:YES];
[self.migrationView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
self.migrationView = nil;
self.migrationProgressLabel = nil;
self.migrationProgressView = nil;
self.migrationSpinner = nil;
error = nil;
return YES;
}
else
{
migrationProgress = 0.0;
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:NO waitUntilDone:YES];
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
}
//END:progressivelyMigrateURLHappyCheck
//START:progressivelyMigrateURLFindModels
//Find the source model
NSManagedObjectModel *sourceModel = [NSManagedObjectModel mergedModelFromBundles:nil forStoreMetadata:sourceMetadata];
if(sourceModel == nil)
{
NSLog(@"%@", [NSString stringWithFormat:@"Failed to find source model\n%@", [sourceMetadata description]]);
return NO;
}
//Find all of the mom and momd files in the Resources directory
NSMutableArray *modelPaths = [NSMutableArray array];
NSArray *momdArray = [[NSBundle mainBundle] pathsForResourcesOfType:@"momd" inDirectory:nil];
for (NSString *momdPath in momdArray)
{
NSAutoreleasePool *pool = [NSAutoreleasePool new];
NSString *resourceSubpath = [momdPath lastPathComponent];
NSArray *array = [[NSBundle mainBundle] pathsForResourcesOfType:@"mom" inDirectory:resourceSubpath];
[modelPaths addObjectsFromArray:array];
[pool drain];
}
NSArray* otherModels = [[NSBundle mainBundle] pathsForResourcesOfType:@"mom" inDirectory:nil];
[modelPaths addObjectsFromArray:otherModels];
if (!modelPaths || ![modelPaths count])
{
//Throw an error if there are no models
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setValue:@"No models found in bundle" forKey:NSLocalizedDescriptionKey];
//Populate the error
error = [NSError errorWithDomain:@"com.yongopal.coredata" code:500 userInfo:dict];
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
return NO;
}
//END:progressivelyMigrateURLFindModels
//See if we can find a matching destination model
//START:progressivelyMigrateURLFindMap
NSMappingModel *mappingModel = nil;
NSManagedObjectModel *targetModel = nil;
NSString *modelPath = nil;
for(modelPath in modelPaths)
{
targetModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:[NSURL fileURLWithPath:modelPath]];
mappingModel = [NSMappingModel mappingModelFromBundles:nil forSourceModel:sourceModel destinationModel:targetModel];
//If we found a mapping model then proceed
if(mappingModel)
{
break;
}
else
{
//Release the target model and keep looking
[targetModel release];
targetModel = nil;
}
}
//We have tested every model, if nil here we failed
if (!mappingModel)
{
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setValue:@"No mapping models found in bundle" forKey:NSLocalizedDescriptionKey];
error = [NSError errorWithDomain:@"com.yongopal.coredata" code:500 userInfo:dict];
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
return NO;
}
//END:progressivelyMigrateURLFindMap
//We have a mapping model and a destination model. Time to migrate
//START:progressivelyMigrateURLMigrate
NSMigrationManager *manager = [[NSMigrationManager alloc] initWithSourceModel:sourceModel destinationModel:targetModel];
// reg KVO for migration progress
[manager addObserver:self forKeyPath:@"migrationProgress" options:NSKeyValueObservingOptionNew context:NULL];
NSString *modelName = [[modelPath lastPathComponent] stringByDeletingPathExtension];
NSString *storeExtension = [[sourceStoreURL path] pathExtension];
NSString *storePath = [[sourceStoreURL path] stringByDeletingPathExtension];
//Build a path to write the new store
storePath = [NSString stringWithFormat:@"%@.%@.%@", storePath, modelName, storeExtension];
NSURL *destinationStoreURL = [NSURL fileURLWithPath:storePath];
if (![manager migrateStoreFromURL:sourceStoreURL type:type options:nil withMappingModel:mappingModel toDestinationURL:destinationStoreURL destinationType:type destinationOptions:nil error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
[targetModel release];
[manager removeObserver:self forKeyPath:@"migrationProgress"];
[manager release];
return NO;
}
[targetModel release];
[manager removeObserver:self forKeyPath:@"migrationProgress"];
[manager release];
//END:progressivelyMigrateURLMigrate
//Migration was successful, move the files around to preserve the source
//START:progressivelyMigrateURLMoveAndRecurse
NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString];
guid = [guid stringByAppendingPathExtension:modelName];
guid = [guid stringByAppendingPathExtension:storeExtension];
NSString *appSupportPath = [storePath stringByDeletingLastPathComponent];
NSString *backupPath = [appSupportPath stringByAppendingPathComponent:guid];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager moveItemAtPath:[sourceStoreURL path] toPath:backupPath error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
//Failed to copy the file
return NO;
}
//Move the destination to the source path
if (![fileManager moveItemAtPath:storePath toPath:[sourceStoreURL path] error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
//Try to back out the source move first, no point in checking it for errors
[fileManager moveItemAtPath:backupPath toPath:[sourceStoreURL path] error:nil];
return NO;
}
//We may not be at the "current" model yet, so recurse
return [self progressivelyMigrateURL:sourceStoreURL ofType:type toModel:finalModel];
//END:progressivelyMigrateURLMoveAndRecurse
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"YongoPal.sqlite"];
// perform core data migrations if necessary
if(![self progressivelyMigrateURL:storeURL ofType:NSSQLiteStoreType toModel:self.managedObjectModel])
{
// reset the persistent store on fail
NSString *documentDir = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
NSError *error = nil;
[[NSFileManager defaultManager] removeItemAtPath:[NSBundle pathForResource:@"YongoPal" ofType:@"sqlite" inDirectory:documentDir] error:&error];
}
else
{
NSLog(@"migration succeeded!");
}
请记住在使用此选项之前删除轻量级迁移选项。我以前也遇到过同样的问题 我有一种方法，可以尝试使用映射模型来迁移数据，如果要关闭轻量级迁移，应该使用映射模型 如果您不打算进行大量的数据映射，xcode将自动创建一个映射模型，该模型的工作方式与轻量级迁移完全相同。每次向核心数据添加新版本时，只需创建一个新的“映射模型”文件。只需进入“文件->新建->新建文件”，在核心数据下应该有一个映射模型模板。选择它并选择源和目标版本 我没有在github上公开我的代码，所以我只在这里发布迁移方法
- (BOOL)progressivelyMigrateURL:(NSURL*)sourceStoreURL ofType:(NSString*)type toModel:(NSManagedObjectModel*)finalModel
{
NSError *error = nil;
// if store dosen't exist skip migration
NSString *documentDir = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
if(![NSBundle pathForResource:@"YongoPal" ofType:@"sqlite" inDirectory:documentDir])
{
migrationProgress = 1.0;
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
// remove migration view
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:[NSNumber numberWithBool:YES] waitUntilDone:YES];
[self.migrationView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
self.migrationView = nil;
self.migrationProgressLabel = nil;
self.migrationProgressView = nil;
self.migrationSpinner = nil;
return YES;
}
//START:progressivelyMigrateURLHappyCheck
NSDictionary *sourceMetadata = [NSPersistentStoreCoordinator metadataForPersistentStoreOfType:type URL:sourceStoreURL error:&error];
if (!sourceMetadata)
{
return NO;
}
if ([finalModel isConfiguration:nil compatibleWithStoreMetadata:sourceMetadata])
{
migrationProgress = 1.0;
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
// remove migration view
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:[NSNumber numberWithBool:YES] waitUntilDone:YES];
[self.migrationView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
self.migrationView = nil;
self.migrationProgressLabel = nil;
self.migrationProgressView = nil;
self.migrationSpinner = nil;
error = nil;
return YES;
}
else
{
migrationProgress = 0.0;
[self.migrationView performSelectorOnMainThread:@selector(setHidden:) withObject:NO waitUntilDone:YES];
[self performSelectorOnMainThread:@selector(updateMigrationProgress) withObject:nil waitUntilDone:YES];
}
//END:progressivelyMigrateURLHappyCheck
//START:progressivelyMigrateURLFindModels
//Find the source model
NSManagedObjectModel *sourceModel = [NSManagedObjectModel mergedModelFromBundles:nil forStoreMetadata:sourceMetadata];
if(sourceModel == nil)
{
NSLog(@"%@", [NSString stringWithFormat:@"Failed to find source model\n%@", [sourceMetadata description]]);
return NO;
}
//Find all of the mom and momd files in the Resources directory
NSMutableArray *modelPaths = [NSMutableArray array];
NSArray *momdArray = [[NSBundle mainBundle] pathsForResourcesOfType:@"momd" inDirectory:nil];
for (NSString *momdPath in momdArray)
{
NSAutoreleasePool *pool = [NSAutoreleasePool new];
NSString *resourceSubpath = [momdPath lastPathComponent];
NSArray *array = [[NSBundle mainBundle] pathsForResourcesOfType:@"mom" inDirectory:resourceSubpath];
[modelPaths addObjectsFromArray:array];
[pool drain];
}
NSArray* otherModels = [[NSBundle mainBundle] pathsForResourcesOfType:@"mom" inDirectory:nil];
[modelPaths addObjectsFromArray:otherModels];
if (!modelPaths || ![modelPaths count])
{
//Throw an error if there are no models
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setValue:@"No models found in bundle" forKey:NSLocalizedDescriptionKey];
//Populate the error
error = [NSError errorWithDomain:@"com.yongopal.coredata" code:500 userInfo:dict];
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
return NO;
}
//END:progressivelyMigrateURLFindModels
//See if we can find a matching destination model
//START:progressivelyMigrateURLFindMap
NSMappingModel *mappingModel = nil;
NSManagedObjectModel *targetModel = nil;
NSString *modelPath = nil;
for(modelPath in modelPaths)
{
targetModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:[NSURL fileURLWithPath:modelPath]];
mappingModel = [NSMappingModel mappingModelFromBundles:nil forSourceModel:sourceModel destinationModel:targetModel];
//If we found a mapping model then proceed
if(mappingModel)
{
break;
}
else
{
//Release the target model and keep looking
[targetModel release];
targetModel = nil;
}
}
//We have tested every model, if nil here we failed
if (!mappingModel)
{
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[dict setValue:@"No mapping models found in bundle" forKey:NSLocalizedDescriptionKey];
error = [NSError errorWithDomain:@"com.yongopal.coredata" code:500 userInfo:dict];
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
return NO;
}
//END:progressivelyMigrateURLFindMap
//We have a mapping model and a destination model. Time to migrate
//START:progressivelyMigrateURLMigrate
NSMigrationManager *manager = [[NSMigrationManager alloc] initWithSourceModel:sourceModel destinationModel:targetModel];
// reg KVO for migration progress
[manager addObserver:self forKeyPath:@"migrationProgress" options:NSKeyValueObservingOptionNew context:NULL];
NSString *modelName = [[modelPath lastPathComponent] stringByDeletingPathExtension];
NSString *storeExtension = [[sourceStoreURL path] pathExtension];
NSString *storePath = [[sourceStoreURL path] stringByDeletingPathExtension];
//Build a path to write the new store
storePath = [NSString stringWithFormat:@"%@.%@.%@", storePath, modelName, storeExtension];
NSURL *destinationStoreURL = [NSURL fileURLWithPath:storePath];
if (![manager migrateStoreFromURL:sourceStoreURL type:type options:nil withMappingModel:mappingModel toDestinationURL:destinationStoreURL destinationType:type destinationOptions:nil error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
[targetModel release];
[manager removeObserver:self forKeyPath:@"migrationProgress"];
[manager release];
return NO;
}
[targetModel release];
[manager removeObserver:self forKeyPath:@"migrationProgress"];
[manager release];
//END:progressivelyMigrateURLMigrate
//Migration was successful, move the files around to preserve the source
//START:progressivelyMigrateURLMoveAndRecurse
NSString *guid = [[NSProcessInfo processInfo] globallyUniqueString];
guid = [guid stringByAppendingPathExtension:modelName];
guid = [guid stringByAppendingPathExtension:storeExtension];
NSString *appSupportPath = [storePath stringByDeletingLastPathComponent];
NSString *backupPath = [appSupportPath stringByAppendingPathComponent:guid];
NSFileManager *fileManager = [NSFileManager defaultManager];
if (![fileManager moveItemAtPath:[sourceStoreURL path] toPath:backupPath error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
//Failed to copy the file
return NO;
}
//Move the destination to the source path
if (![fileManager moveItemAtPath:storePath toPath:[sourceStoreURL path] error:&error])
{
if([[self.prefs valueForKey:@"debugMode"] isEqualToString:@"Y"])
{
NSLog(@"error: %@", error);
}
//Try to back out the source move first, no point in checking it for errors
[fileManager moveItemAtPath:backupPath toPath:[sourceStoreURL path] error:nil];
return NO;
}
//We may not be at the "current" model yet, so recurse
return [self progressivelyMigrateURL:sourceStoreURL ofType:type toModel:finalModel];
//END:progressivelyMigrateURLMoveAndRecurse
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"YongoPal.sqlite"];
// perform core data migrations if necessary
if(![self progressivelyMigrateURL:storeURL ofType:NSSQLiteStoreType toModel:self.managedObjectModel])
{
// reset the persistent store on fail
NSString *documentDir = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
NSError *error = nil;
[[NSFileManager defaultManager] removeItemAtPath:[NSBundle pathForResource:@"YongoPal" ofType:@"sqlite" inDirectory:documentDir] error:&error];
}
else
{
NSLog(@"migration succeeded!");
}
在您的示例中，您将在含义已更改的字段上执行此操作。我不明白此代码如何解决我的问题。重申一下，我需要一种方式来说明这两种模式是不兼容的。在XCode中创建映射模型文件后，我应该对它做些什么吗？创建映射模型后，请尝试从XCode（4.x）中查看它，它应该会列出实体映射和属性映射的列表。在属性映射列表中，您应该可以看到目标和值表达式。只需删除要从迁移中排除的属性的值表达式（看起来应该像$source.{attribute_name}），使其为空。当您运行我的ProgressiveyMigrateUrl:ofType:toModel:方法时，它将迁移除具有空值表达式的属性之外的所有属性。该方法来自Marcus S.Zarra的“Core Data:Apple API，用于在Mac OSX上持久化数据”。我认为它现在被称为“核心数据：iOS、OSX和iCloud的数据存储和管理”。我不明白这段代码如何解决我的问题。重申一下，我需要一种方式来说明这两种模式是不兼容的。在XCode中创建映射模型文件后，我应该对它做些什么吗？创建映射模型后，请尝试从XCode（4.x）中查看它，它应该会列出实体映射和属性映射的列表。在属性映射列表中，您应该可以看到目标和值表达式。只需删除要从迁移中排除的属性的值表达式（看起来应该像$source.{attribute_name}），使其为空。当您运行我的ProgressiveyMigrateUrl:ofType:toModel:方法时，它将迁移除具有空值表达式的属性之外的所有属性。该方法来自Marcus S.Zarra的“Core Data:Apple API，用于在Mac OSX上持久化数据”。我认为它现在被称为“核心数据：iOS、OSX和iCloud的数据存储和管理”。。