Here's the final code example that uses both Core Data and Realm to interact with a database.

Fixing Common Issues with Core Data: A Guide to Avoiding NSInvalidArgumentException Errors

Understanding the Problem of App Terminating on Back Button in iOS 7: A New Approach to Resolving the Issue

Understanding Static Linking of SQLite on iPhone: A Comprehensive Guide for iOS Developers

How to Prevent and Mitigate SIGPIPE Crashes in C Applications