大佬教程收集整理的这篇文章主要介绍了iOS:如何创建核心数据库的备份副本?以及如何导出/导入该副本?,大佬教程大佬觉得挺不错的,现在分享给大家,也给大家做个参考。
我该怎么办?特别是如何重新导入该文件?我的意思是让我们说他制作了数据库的备份副本,然后改变了大量的东西,并希望重置为之前保存的备份副本.我该怎么办?
谢谢!
顺便说一句,如果您要在ICloud之间进行备份,那么使用migratePersistentStore API来制作/导入备份会更安全.另请注意,示例应用程序假定您没有使用WAL模式,这是iOS 7的默认模式.WAL模式使用多个文件,这些文件都需要备份或复制.
以下是用于创建备份副本的方法.请注意,可以使用多个persistentStoreCoordinator打开存储,因此在进行备份时无需关闭它.恢复它显然需要先删除现有的商店.请注意,除了使用或不使用iCloud选项打开源存储之外,以下两种方法之间几乎没有区别.
/*! Creates a BACkup of the ICloud store @return Returns YES of file was migrated or NO if not. */ - (bool)BACkupICloudStore { FLOG(@"BACkupICloudStore called"); // Lets use the exisTing PSC NSPersistentStoreCoordinator *migrationPSC = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel]; // Open the store id @R_450_9016@eStore = [migrationPSC addPersistentStoreWithType:NSsqliteStoreType configuration:nil URL:[self icloudStoreURL] options:[self icloudStoreOptions] error:nil]; if (!@R_450_9016@eStorE) { FLOG(@" Failed to add old store"); migrationPSC = nil; return falSE; } else { FLOG(@" successfully added store to migrate"); NSError *error; FLOG(@" About to migrate the store..."); id migrationsuccess = [migrationPSC migratePersistentStore:@R_450_9016@eStore toURL:[self BACkupStoreURL] options:[self localStoreOptions] withType:NSsqliteStoreType error:&error]; if (migrationsuccess) { FLOG(@"store successfully BACked up"); migrationPSC = nil; // Now reset the BACkup preference [[NSUserDefaults standardUserDefaults] setBool:NO forKey:_makeBACkupPreferenceKey]; [[NSUserDefaults standardUserDefaults] synchronize]; return TRUE; } else { FLOG(@"Failed to BACkup store: %@,%@",error,error.userInfo); migrationPSC = nil; return falSE; } } migrationPSC = nil; return falSE; } /*! Creates a BACkup of the Local store @return Returns YES of file was migrated or NO if not. */ - (bool)BACkupLocalStore { FLOG(@"BACkupLocalStore called"); // Lets use the exisTing PSC NSPersistentStoreCoordinator *migrationPSC = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel]; // Open the store id @R_450_9016@eStore = [migrationPSC addPersistentStoreWithType:NSsqliteStoreType configuration:nil URL:[self localStoreURL] options:[self localStoreOptions] error:nil]; if (!@R_450_9016@eStorE) { FLOG(@" Failed to add old store"); migrationPSC = nil; return falSE; } else { FLOG(@" successfully added store to migrate"); NSError *error; FLOG(@" About to migrate the store..."); id migrationsuccess = [migrationPSC migratePersistentStore:@R_450_9016@eStore toURL:[self BACkupStoreURL] options:[self localStoreOptions] withType:NSsqliteStoreType error:&error]; if (migrationsuccess) { FLOG(@"store successfully BACked up"); migrationPSC = nil; // Now reset the BACkup preference [[NSUserDefaults standardUserDefaults] setBool:NO forKey:_makeBACkupPreferenceKey]; [[NSUserDefaults standardUserDefaults] synchronize]; return TRUE; } else { FLOG(@"Failed to BACkup store: %@,error.userInfo); migrationPSC = nil; return falSE; } } migrationPSC = nil; return falSE; } /** Sets the SELEcted file as the current store. Creates a BACkup of the current store first. @param fileURL The URL for the file to use. */ - (BOOL)restoreFile:(NSURL *)fileURL { FLOG(@" called"); // check if we are using iCloud if (_isCloudEnabled) { FLOG(@" using iCloud store so OK to restore"); NSURL *currentURL = [self storeURL]; FLOG(@" currentURL is %@",currentURL); FLOG(@" URL to use is %@",fileURL); [self saveContext]; [self BACkupCurrentStoreWithNocheck]; // Close the current store and delete it _persistentStoreCoordinator = nil; _managedObjectContext = nil; [self removeICloudStore]; [self moveStoreFileToICloud:fileURL delete:NO BACkup:NO]; } else { FLOG(@" using local store so OK to restore"); NSURL *currentURL = [self storeURL]; FLOG(@" currentURL is %@",fileURL); [self saveContext]; [self BACkupCurrentStoreWithNocheck]; // Close the current store and delete it _persistentStoreCoordinator = nil; _managedObjectContext = nil; NSError *error = nil; NSFileManager *fm = [[NSFileManager alloc] init]; // delete the current store file if ([fm fileExistsAtPath:[currentURL path]]) { FLOG(@" target file exists"); if (![fm removeItemAtURL:currentURL error:&error]) { FLOG(@" error unable to remove current store file"); NSLog(@"Error removing item Error: %@,error.userInfo); return falSE; } else { FLOG(@" current store file removed"); } } // //simply copy the file over BOOL copysuccess = [fm copyItemAtPath:[fileURL path] toPath:[currentURL path] error:&error]; if (copysuccess) { FLOG(@" replaced current store file successfully"); //[self postFileupdateNotification]; } else { FLOG(@"Error copying items Error: %@,error.userInfo); return falSE; } } // Now open the store again [self openPersistentStore]; return TRUE; }
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