Revelation Software Labs interview question

1. Single Table Inheritance (STI) 2. Difference b/w Inner and Outer Join 3. Include vs Extend 4. What is concerns in Rails 5. What if Superclass and Class having the same function name and we call a method from the instance of the Class. Which method would be called? 6. How to authenticate API token? 7. Polymorphic Association 8. Garbage Collection 9. Types of Caching 10. What is Memory Leakage 11. What is yield in Rails