Automatically deleting our persistent store upon model changes in early development of @nutshellcrm

gistfile1.m

#define kIncompatibleModelErrorReason @"The model used to open the store is incompatible with the one used to create the store"

/**
 Returns the persistent store coordinator for the application.
 If the coordinator doesn't already exist, it is created and the application's store added to it.
 */
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
    if (persistentStoreCoordinator_ != nil) {
        return persistentStoreCoordinator_;
    }
    
    NSURL *storeUrl = [NSURL fileURLWithPath: [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:kStoreName]];
    
    NSError *error = nil;
    persistentStoreCoordinator_ = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:self.managedObjectModel];
    
    if (![persistentStoreCoordinator_ addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeUrl options:nil error:&error]) {
        if ([[[error userInfo] objectForKey:@"reason"] isEqualToString:kIncompatibleModelErrorReason]) {
            NSFileManager *fileManager = [NSFileManager defaultManager];
            
            if ([fileManager removeItemAtURL:storeUrl error:NULL]) {
                persistentStoreCoordinator_ = nil;
                return [self persistentStoreCoordinator];
            }
        } else {
            /**
             * Replace this implementation with code to handle other errors 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. If 
             * it is not possible to recover from the error, display an alert panel that instructs the 
             * user to quit the application by pressing the Home button.
             */
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        }
        abort();
    }    
    
    return persistentStoreCoordinator_;
}