Can I use two separate SQLite databases?

Question

I have one sqlite database in which I store both user information and read-only information. I feel that I may need to change read-only information in the future, and I do not want to do all the data migration. Is there a way that I can use a separate sqlite database that can be easily replaced for read-only information? If so, can you give a little guidance on how this can be done? I am confused since I currently have all the objects on xcdatamodel - would I create two data models? Not sure how this will work. Thanks in advance.

---

This does not work, but please feel free to give feedback.

- (NSManagedObjectModel *)managedObjectModel {

    NSLog(@"%s", __FUNCTION__);
    if (managedObjectModel != nil) {
        return managedObjectModel;
    }
    //managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];

    NSString *mainPath = [[NSBundle mainBundle] pathForResource:@"MyApp" ofType:@"mom"];
    NSURL *mainMomURL = [NSURL fileURLWithPath:mainPath];
    managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:mainMomURL];

    [managedObjectModel setEntities:[NSArray arrayWithObjects:
                                          [[managedObjectModel entitiesByName] objectForKey:@"Version"],
                                          [[managedObjectModel entitiesByName] objectForKey:@"Book"],
                                          nil] forConfiguration:@"info"];

    [managedObjectModel setEntities:[NSArray arrayWithObjects:
                                          [[managedObjectModel entitiesByName] objectForKey:@"Settings"],
                                          [[managedObjectModel entitiesByName] objectForKey:@"Persons"],
                                          nil] forConfiguration:@"main"];

    return managedObjectModel;
}

and

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {

    NSLog(@"%s", __FUNCTION__);
    if (persistentStoreCoordinator != nil) {
        return persistentStoreCoordinator;
    }

    NSString *storePath = [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Main.sqlite"];

    NSFileManager *fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:storePath]) {
        NSString *defaultStorePath = [[NSBundle mainBundle] pathForResource:@"Default" ofType:@"sqlite"];
        if (defaultStorePath) {
            [fileManager copyItemAtPath:defaultStorePath toPath:storePath error:NULL];
        }
    }

    NSURL *storeUrl = [NSURL fileURLWithPath:storePath];
    NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];    


    NSString *infoStorePath = [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Info.sqlite"];
    if (![fileManager fileExistsAtPath:infoStorePath]) {
        NSString *defaultInfoStorePath = [[NSBundle mainBundle] pathForResource:@"DefaultInfo" ofType:@"sqlite"];
        if (defaultInfoStorePath) {
            [fileManager copyItemAtPath:defaultInfoStorePath toPath:infoStorePath error:NULL];
        }
    }

    NSURL *infoStoreUrl = [NSURL fileURLWithPath:infoStorePath];

    persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];
    //persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] init]; 

    NSPersistentStore *mainStore = [persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:@"main" URL:storeUrl options:options error:&error];
    NSPersistentStore *infoStore = [persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:@"verses" URL:infoStoreUrl options:options error:&error];

    NSManagedObject *settingsEntity = [[NSManagedObject alloc] initWithEntity:[[managedObjectModel entitiesByName] objectForKey:@"Settings"] insertIntoManagedObjectContext:self.managedObjectContext];
    [self.managedObjectContext assignObject:settingsEntity toPersistentStore:mainStore];

    NSManagedObject *persons = [[NSManagedObject alloc] initWithEntity:[[managedObjectModel entitiesByName] objectForKey:@"Persons"] insertIntoManagedObjectContext:self.managedObjectContext];
    [self.managedObjectContext persons toPersistentStore:mainStore];

NSManagedObject *version = [[NSManagedObject alloc] initWithEntity:[[managedObjectModel entitiesByName] objectForKey:@"Version"] insertIntoManagedObjectContext:self.managedObjectContext];
[self.managedObjectContext assignObject:version toPersistentStore:infoStore];

NSManagedObject *book = [[NSManagedObject alloc] initWithEntity:[[managedObjectModel entitiesByName] objectForKey:@"Book"] insertIntoManagedObjectContext:self.managedObjectContext];
[self.managedObjectContext assignObject:book toPersistentStore:infoStore];

and

- (NSManagedObjectContext *)managedObjectContext {

    NSLog(@"%s", __FUNCTION__);
    if (managedObjectContext != nil) {
        return managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil) {
        managedObjectContext = [NSManagedObjectContext new];
        [managedObjectContext setPersistentStoreCoordinator: coordinator];
    }
    return managedObjectContext;
}

Answer 1

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Answer 2

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Answer 3

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NSPersistentStoreCoordinator *coord = [[NSPersistentStoreCoordinator alloc] init];
NSPersistentStore *userStore = [coord addPersistentStoreWithType:NSSQLiteStore configuration:nil URL:someFileURL options:someoptions error:&error];
NSPersistentStore *otherStore = [coord addPersistentStoreWithType:NSSQLiteStore configuration:nil URL:someFileURL2 options:someoptions error:&error];

//Now you use the two separate stores through a managed object context that references the coordinator
NSManagedObjectContext *context = [[NSManagedObjectContext alloc] init];
[context setPersistentStoreCoordinator:coord];

NSManagedObject *userObject = [[NSManagedObject alloc] initWithEntity:entityDescFromModel insertIntoManagedObjectContext:context];
[context assignObject:userObject toPersistentStore:userStore];

NSManagedObject *otherObject = [[NSManagedObject alloc] initWithEntity:entityDescFromModel insertIntoManagedObjectContext:context];
[context assignObject:otherObject toPersistentStore:otherStore];

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Answer 4

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