Questions 1 and 5 do not have enough details to provide an answer. I would be asking for a lot of clarity about what those mean. 2, 3 and 4 are not questions that have an answer. They are intended to start a discussion about how to do those things. This is more of a role playing technique than anything else. If you can discuss a number of things you would do that is what they are after. Of all of those I find the "how do you optimize a procedure" to be the most outlandish of them all. The interviewer wants to see if you know that the question is loaded. There is not a formula for this. It is more of an art than a science. Optimizing queries takes the culmination of all your knowledge in one location. Even worse is that you might optimize a query today and in a year you go back and realize a number of improvements you could make because you have learned new things.