DataBase Administrator (DBA) Interview Questions and Answers
What is a DBA?
A DBA is a Database Administrator, and this is the most common job that you find a database specialist doing. There are Development DBAs and Production DBAs.
1. What DBA activities did you to do today?
This is a loaded question and almost begs for you to answer it with "What DBA activities do you LIKE to do on a daily basis?." And that is how I would answer this question. Again, do not get caught up in the "typical" day-to-day operational issues of database administration. Sure, you can talk about the index you rebuilt, the monitoring of system and session waits that were occurring, or the space you added to a data file, these are all good and great and you should convey that you understand the day-to-day operational issues. What you should also throw into this answer are the meetings that you attend to provide direction in the database arena, the people that you meet and talk with daily to answer adhoc questions about database use, the modeling of business needs within the database, and the extra time you spend early in the morning or late at night to get the job done. Just because the question stipulates "today" do not take "today" to mean "today." Make sure you wrap up a few good days into "today" and talk about them. This question also begs you to ask the question of "What typical DBA activities are performed day to day within X Corporation?"
2. What are the different modes of mounting a Database with the Parallel Server?
Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database. Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database.
3. What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode?
Complete database recovery from disk failure is possible only in ARCHIVELOG mode. Online database backup is possible only in ARCHIVELOG mode.
4. Do you consider yourself a development DBA or a production DBA and why?
You take this as a trick question and explain it that way. Never in my database carrier have I distinguished between "development" and "production." Just ask your development staff or VP of engineering how much time and money is lost if development systems are down. Explain to the interviewer that both systems are equally important to the operation of the company and both should be considered as production systems because there are people relying on them and money is lost if either one of them is down. Ok you may be saying, and I know you are, that we lose more money if the production system is down. Ok, convey that to the interviewer and you won't get anyone to disagree with you unless your company sells software or there are million dollar deals on the table that are expecting the next release of your product or service.
5. What are the Large object types suported by Oracle?
6. Diffrence between a “where” clause and a “having” claus
7. Shall we create procedures to fetch more than one record?
Yes. We can create procedures to fetch more than a row.
By using CURSOR commands we could able to do that.
(Continued on next part...)