Tim Young [Elevate Software] wrote:

>
> Not really - I just know for a fact that most of the time I don't know for
> sure.

It's a rare person who knows what he doesn't know and even rarer when he/she
confesses to it.


Ian

Ian,

> Maybe I'm still thinking old school rather than the SQL type world but I
> thought that inherently indexs (what is the official plural of index?), or
more
> specifically the fields that are indexed, could not be variable in length.
I don't know how Tim realized the indexes but most databases (Oracle, MS SQL
etc) uses the b-trees and there length of value is not important

--
With best regards, Mike Shkolnik
E-mail: mshkolnik@scalabium.com
WEB: http://www.scalabium.com

Hi Mike,

Mike Shkolnik wrote:

> I don't know how Tim realized the indexes but most databases (Oracle, MS SQL
> etc) uses the b-trees and there length of value is not important

Ahhhh.  OK.  Technology gap, mine. Thanks for the clarification.

Regards

Ian

--

> VarChar, by my understanding, varies its physical length up to the defined
> length, therefore the effective field length is varying which index's don't
> like.
Consider simple sorted StringList - which would be the most basic
implementation of an index. Is it important, that all strings could be
different length? Even if the length is very large? Will it still sort
strings and be able to locate them using Find? It sure will. Ergo: the
length of string doesn't matter that much You can index anything
no matter how long as soon as your storage can handle that. However,
obviously, indexing very long fields makes usually little or no sense.


Regards,
Michael

Mike (Shkolnik),

<< what is the official plural of index? >>

Depends...
if you're old fashioned and learned Latin: indices
if you're more modern and laid-back: indexes

Regards,
Dan

> << what is the official plural of index? >>
> Depends...
> if you're old fashioned and learned Latin: indices
> if you're more modern and laid-back: indexes
Search in Google:
"indicies": 40 300 000
"indexes": 69 900 000


But anyway for database and web products the "indexes" is more popular. Just
read the documentation for Oracle or Apache
--
With best regards, Mike Shkolnik
EMail: mshkolnik@scalabium.com
http://www.scalabium.com

Mike,

<<Search in Google:
"indicies": 40 300 000
"indexes": 69 900 000 >>

Not on my Google! This is what I found:
"indicies":     437 000   - this is a common typo for the "Latin" plural
"indices": 106 000 000   - this is the correct Latin plural
"indexes": 151 000 000   - and this is how we'll all spell it soon

Dan

Ian,

<< Maybe I'm still thinking old school rather than the SQL type world but I
thought that inherently indexs (what is the official plural of index?), or
more specifically the fields that are indexed, could not be variable in
length.  A VarChar, by my understanding, varies its physical length up to
the defined length, therefore the effective field length is varying which
index's don't like. >>

BTrees, like any page-oriented structure, can use variable-length "items" in
their pages.  Fixed-length keys are usually faster and maintain the most
consistent search times due to the ability to use binary searches on the
keys in each page, however variable-length keys certainly do save space.

--
Tim Young
Elevate Software
www.elevatesoft.com

Ian,

<< It's a rare person who knows what he doesn't know and even rarer when
he/she confesses to it.>>

That's just it - I don't know what I don't know, so how could I confess to
it ?

--
Tim Young
Elevate Software
www.elevatesoft.com