Sean Hull wrote a few interview questions for Database Journal dealing mostly with Oracle:
- Why is a UNION ALL faster than a UNION?
- What are some advantages to using Oracle's CREATE DATABASE statement to create a new database manually?
- What are three rules of thumb to create good passwords? How would a DBA enforce those rules in Oracle? What business challenges might you encounter?
- Describe the Oracle Wait Interface, how it works, and what it provides. What are some limitations? What do the db_file_sequential_read and db_file_scattered_read events indicate?
- How do you return the top-N results of a query in Oracle? Why doesn't the obvious method work?
- Can Oracle's Data Guard be used on Standard Edition, and if so how? How can you test that the standby database is in sync?
- What is a database link? What is the difference between a public and a private database link? What is a fixed user database link?
The database interview answers are all listed on Database Journal Web site
