How to copy sqlite database when we clicked on a UIButton?

Question

I am storing Some details to coredata as NSString.

 NSEntityDescription *entityDesc=[NSEntityDescription entityForName:@"AddNewVehicle" inManagedObjectContext:self.managedObjectContext];
 NSManagedObject *newObject=[[NSManagedObject alloc]initWithEntity:entityDesc insertIntoManagedObjectContext:self.managedObjectContext];
NSError *error;

        NSString *inStr = [NSString stringWithFormat: @"%d", (int)x];
        [newObject setValue:inStr forKey:@"slNo"];
        [newObject setValue:txt_PlateName.text forKey:@"plateNumber"];
        [newObject setValue:txt_vehicleName.text forKey:@"vname"];
        [self.managedObjectContext save:&error];

Also I have two buttons named Backup Button and restore button.When i cilck on backup button, the Current core data must be duplicate as coredataBackup.sqlite. I was tried the following way:-

 - (IBAction)savedata:(id)sender {

    NSString * databaseName = @"coredata.sqlite";
    NSString * databaseBackupName = @"coredataBackup.sqlite";
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error = nil;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;

    NSString *backupPath = [documentsDir stringByAppendingPathComponent:databaseBackupName];
    NSString *dbPath = [documentsDir stringByAppendingPathComponent:databaseName];

    NSURL *toURL = [NSURL fileURLWithPath:backupPath];

    if([fileManager fileExistsAtPath:backupPath])
    {
        NSLog(@"Checks for backuppath is present ?? Success");
        //get rid of the old copy, only one allowed
        [fileManager removeItemAtPath:backupPath error:&error];
    }

    if([fileManager fileExistsAtPath:dbPath])
    {
        if ([fileManager copyItemAtPath:dbPath toPath:backupPath error:&error]) {
            NSLog(@"Creates backup");
            [toURL setResourceValue:[NSNumber numberWithBool:YES] forKey:NSURLIsExcludedFromBackupKey error:&error];
        } else {
            NSLog(@"Failed to create writable database file with message '%@'.", [error localizedDescription]);
        }
    }}

Result is it will creates the coredataBackup.sqlite file on Documents folder.But not copying current coredata details to new file. i don't know how to create back up for coredata.Please any one give some useful advice.Thanks in advance

Answer 1

You should disable WAL mode in persistentStoreCoordinator method of appDelegate

 NSError *error = nil;
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
NSMutableDictionary *pragmaOptions = [NSMutableDictionary dictionary];

/*ATTETION: disable WAL mode*/
[pragmaOptions setObject:@"DELETE" forKey:@"journal_mode"];
NSNumber *optionYes = [NSNumber numberWithBool:YES];
NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:
                         [NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption,
                         [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption,
                         pragmaOptions, NSSQLitePragmasOption,
                         optionYes,NSMigratePersistentStoresAutomaticallyOption ,nil];
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:options error:&error]) {
    abort();
}

Answer 2

Also Change this :-

NSURL *MainURL = [NSURL fileURLWithPath:dbPath];    
if([fileManager fileExistsAtPath:dbPath])
    {
        if ([fileManager copyItemAtPath:dbPath toPath:backupPath error:&error]) {
            NSLog(@"Creates backup");
            NSLog(@"Creates backup db path %@ backup path %@",dbPath,backupPath);

             [[NSFileManager defaultManager] copyItemAtURL:MainURL toURL:toURL error:&error];

        } else {
            NSLog(@"Failed to create writable database file with message '%@'.", [error localizedDescription]);
        }
    }