Index Organized tables: Please explain use?

Hello List!

     I'm having trouble comprehending the idea of an Index Organized table. The Oracle 8i DBA Bible has this paragraph in it:

     An index-organized table is one in which the entire table is created as an index. All the data is stored in the index, and there

     really is no underlying table. Oracle 8i allows secondary indexes to be created on these tables, allows them to store large

     objects, and allows you to add or modify columns using the ALTER TABLE command.

This is all they wrote. But I dont understand how/why one would store data in the actual index. And if you create an index, don't you need to create it on a specific table? And if there is NO table, then HOW could you create and index on it. And why would you do it even if you could?

Thanks in advance,

     Hannah

P.S. I have decided to go through the *bible* with a fine tooth comb in order to deeply ingrain Oracle 8i (use only 7.34 at work still!), hope you don't mind posts asking for clarification. My goal is to get through the entire book stopping to clarify anything that I do not fully 120% grasp or understand:> Received on Fri Nov 10 2000 - 06:05:39 CST