Microsoft Interview Question

Round - 2 Design Round --------- 1. Visitor Pattern 2. Singleton 3. Static 4. Singleton vs Static 5. Any other approach for logging other than singleton and static 6. How singleton is tightly coupled 7. Inheritance vs Association class - which one to choose - IS-A relationship choose inheritance, HAS-A choose association 8. Events 9. Logger design 10. Db design - he gave me different scenarios and asked me design for the same 11. No sql based db design 12. Challenges faced while designing 13. UML association 14. Rest my current project related questions