Re: leading columns in an index

Well, you're putting Descartes before his horse here (sorry, I couldn't resist). You are studying implementation (Oracle), but asking questions about Relational Theory. You need a basic understanding of Relational Theory before you begin the study of Oracle. It is a common mistake. There are many sources on the web and in print. A search under E.F. Codd or C.J. Date will bring you lots of hits, but you can probably go with something less complicated. Look for a database primer. That being said, a good book that strats with a review of theory, and then moves on is "The Practical SQL Handbook, by Bowman, Wmerson, and Darnovsky ISBN 0-201-44787-8. It is written from a Sybase implementation point-of-view, but is still good anyway, and it comes with a runtime version of Sybase. It ain't Oracle, but it'll get you going. Once you undderstand the theory, your questions will have answered themselves (is that possible?)

"Ryan_Mioko" <Ryan_Mioko_at_email.msn.com> wrote in message news:#xEkv7BnAHA.381_at_cpmsnbbsa07...
> > Is this for a midterm exam, a final, or just a homework >assignment?
 

> :) Yea, I know what you mean. But for what its worth here is my story:
>
> In fact, I'm a philosophy student and I'm intrested in computers. I've
> bought the Oracle DBA manuals and lab books and study them on the
 weekends.
> Unfortunatly, since I'm not a computer science major my school has been
> reluctant to grant me access to their Oracle resources; and the books I'm
> reading ask these "bonus" questions which aren't answered directly in the
> text of the chapter.
>
> So, I thought I'd come to this newsgroup and seek the help of the
 community
> here.
>
> My second question is:
> in an index with more than one column how is uniquness identified?
> My guess was that Oracle performed a concatination procedure and treated
> the two columns as one...but this idea isn't confirmed anywhere in the
 text.
>
> While I'm thinking of it, I've bought the DBA manual from Oracle (which is
> not easy to read at all) and the PL/SQL lab from Prentice Hall, which is
> very simple but asumes one has access to an Oracle system. What good
 books
> are there out there?
>
> Thanks all,
> Ryan
>
>
>
>
>
Received on Mon Feb 26 2001 - 19:56:24 CET