iPhone core data preset

Question

What is the best way to initialize Core Data database with content. My iPhone app will have a static database with products (data and images). How/where to store images, how to pre-populate database?

Answer 1

Here is what I did:

• Create the database inside the iPhone app
• I created the model in XCode and do a query against the database (this creates the database)
• My static data is a CSV file
• Use a Ruby script to read the CSV file
• Use the ruby gem sqlite3 to insert data into the database
• Copy back into project

Alternative:

• Store the CSV/XML file containing data inside the app
• Parse it on startup and create your NSMAnagedObjects

Tools/Resources:

• Base software for editing/viewing a sqlite3 database

Database Location: I'm afraid I don't remember it on the top of my head but when you use the simulator your application will be built and copied into a directory. I think the path to your application will be something like this. The database depending on how it is setup is usually in the Documents folder.

~User/Library/Application Settings/iOS Simulator/<version>/<app id>/

Answer 2

Reference the official Apple docs provide a way to prepopulate data into Core Data: Core Data Books

Within my own application, I replaced the function 'NSPersistentStoreCoordinator' within AppDeledate with this one :

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator{
if (_persistentStoreCoordinator != nil) {
    return _persistentStoreCoordinator;
}

NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"CoreDataBooks.CDBStore"];

/*
 Set up the store.
 For the sake of illustration, provide a pre-populated default store.
 */
NSFileManager *fileManager = [NSFileManager defaultManager];
// If the expected store doesn't exist, copy the default store.
if (![fileManager fileExistsAtPath:[storeURL path]]) {
    NSURL *defaultStoreURL = [[NSBundle mainBundle] URLForResource:@"CoreDataBooks" withExtension:@"CDBStore"];
    if (defaultStoreURL) {
        [fileManager copyItemAtURL:defaultStoreURL toURL:storeURL error:NULL];
    }
}

NSDictionary *options = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];
_persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: [self managedObjectModel]];

NSError *error;
if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:options error:&error]) {
    /*
     Replace this implementation with code to handle the error appropriately.

     abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 

     Typical reasons for an error here include:
     * The persistent store is not accessible;
     * The schema for the persistent store is incompatible with current managed object model.
     Check the error message to determine what the actual problem was.


     If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.

     If you encounter schema incompatibility errors during development, you can reduce their frequency by:
     * Simply deleting the existing store:
     [[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]

     * Performing automatic lightweight migration by passing the following dictionary as the options parameter:
     @{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES}

     Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.

     */
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

return _persistentStoreCoordinator;

}

Hope this works, good luck!