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？

概述我想为我的应用程序的用户提供创建核心数据库备份的可能性,特别是在他切换到新设备等的情况下. 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！ 看看这个示例应用程序,它包括进行备份,从iCloud复制备份,通过电子邮件发送备份和从电子邮件导入备份的功能. http://ossh.com.au/ 我想为我的应用程序的用户提供创建核心数据库备份的可能性,特别是在他切换到新设备等的情况下.

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！

解决方法 看看这个示例应用程序,它包括进行备份,从iCloud复制备份,通过电子邮件发送备份和从电子邮件导入备份的功能.
@L_403_0@

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.

以下是展示示例应用备份和还原功能的视频的链接.

http://ossh.com.au/design-and-technology/software-development/sample-library-style-ios-core-data-app-with-icloud-integration/sample-apps-explanations/backup-files/

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 sourceStore = [migrationPSC addPersistentStoreWithType:NSsqliteStoreType configuration:nil URL:[self icloudStoreURL] options:[self icloudStoreOptions] error:nil];        if (!sourceStore) {            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:sourceStore 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 sourceStore = [migrationPSC addPersistentStoreWithType:NSsqliteStoreType configuration:nil URL:[self localStoreURL] options:[self localStoreOptions] error:nil];        if (!sourceStore) {            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:sourceStore 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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