Database Interview Questions

   What are the different types of joins? 

   Explain normalization with examples. 

   What cursor type do you use to retrieve multiple record sets? 

   Difference between a "where" clause and a "having" clause 

   What is the difference between "procedure" and "function"? 

   How will you copy the structure of a table without copying the data? 

   How to find out the database name from SQL*PLUS command prompt? 

   Takeoffs with having indexes 

   Talk about "Exception Handling" in PL/SQL? 

   What is the difference between "NULL in C" and "NULL in Oracle?" 

   What is Pro*C? What is OCI? 

   Give some examples of Analytical functions. 

   What is the difference between "translate" and "replace"? 

   What is DYNAMIC SQL method 4? 

   How to remove duplicate records from a table? 

   What is the use of analyzing the tables? 

   How to run SQL script from a Unix Shell? 

   What is a "transaction"? Why are they necessary? 

   Explain Normalization and Demoralization with examples. 

   When do you get constraint violation? What are the types of constraints? 

   How to convert RAW data type into TEXT? 

   Difference - Primary Key and Aggregate Key 

   How functional dependency is related to database table design? 

   What is a "trigger"? 

   Why can a "group by" or "order by" clause be expensive to process? 

   What are "HINTS"? What is "index covering" of a query? 

   What is a VIEW? How to get script for a view? 

   What are the Large object types supported by Oracle? 

   What is SQL*Loader? 

   Difference between "VARCHAR" and "VARCHAR2" data types. 

   What is the difference among "dropping a table", "truncating a table" and "deleting all records" from a table? 

   Difference between "ORACLE" and "MICROSOFT ACCESS" databases. 

   How to create a database link? 

A Brief History of Oracle

Way back in June 1970, Dr E F Codd published a paper entitled A Relational Model of Data for Large Shared Data Banks. This relational model, sponsored by IBM, then came to be accepted as the definitive model for relational database management systems – RDBMS. The language developed by IBM to manipulate the data stored within Codd's model was originally called Structured English Query Language, or SEQUEL, with the word 'English' later being dropped in favor Structured Query Language – SQL.

In 1979 a company called Relational Software, Inc. released the first commercially available implementation of SQL. Relational Software later came to be known as Oracle Corporation.

Today, the Oracle DBMS is supported on over 80 different operating environments, ranging from IBM mainframes, DEC VAX minicomputers, UNIX-based minicomputers, Windows NT and several proprietary hardware-operating system platforms, and is clearly the world's largest RDBMS vendor.

Oracle employs more than 42,000 professionals in 93 countries around the world. Their expenditure for research and development is approximately 13% of their revenues.

Lawrence Joseph (Larry) Ellison (Born: 1944, Chicago) is president and CEO of Oracle corporation.

He's the Oracle worlds hero, and he should be. Oracle Corporation, the company he founded with Robert N. (Bob) Miner and Edward A. (Ed) Oates back in 1977, has emerged as the world's largest vendor of software that helps large corporations and governments better manage their information.

(Below is taken from ORAFAQ)

So, who is Scott?

Bruce Scott was one of the first employees at Oracle (then Software Development Laboratories). He co-founded Gupta Technology (now known as Centura Software) in 1984 with Umang Gupta, and later became CEO and founder of PointBase, Inc.

Bruce was co-author and co-architect of Oracle V1, V2 and V3. The SCOTT schema (EMP and DEPT tables), with password TIGER, was created by him. Tiger was the name of his cat.

Where did the word Oracle originate from?

The word Oracle means:

"Prophecy or prediction; answer to a question believed to come from the gods; a statement believed to be infallible and authoritative; a shrine at which these answers are given"

There is, however, more to the word Oracle: used for the name of the database engine, and then later for the company itself. Larry Ellison and Bob Miner were working on a consulting project for the CIA (Central Intelligence Agency in USA) where the CIA wanted to use this new SQL language that IBM had written a white paper about. The code name for the project was Oracle (the CIA saw this as the system to give all answers to all questions or something such ;-).

The project eventually died (of sorts) but Larry and Bob saw the opportunity to take what they had started and market it. So they used that project's codename of Oracle to name their new RDBMS engine. Funny thing is, that one of Oracle's first customers was the CIA...

How fast is the Oracle database?

The standard Oracle license agreement normally prevents users from publishing benchmark results. The best source for performance related data is the Transaction Processing Performance Council (TPC). Visit their Home Page for database benchmark results.