Path: utzoo!attcan!uunet!dev!dgis!jkrueger
From: jkrueger@dgis.dtic.dla.mil (Jon)
Newsgroups: comp.databases
Subject: Re: Summary: Full Text Database Products
Keywords: full text storage retrieval
Message-ID: <771@dgis.dtic.dla.mil>
Date: 21 Feb 90 14:45:55 GMT
References: <1990Jan30.204658.1822@comp.vuw.ac.nz> <1990Feb19.235547.8915@comp.vuw.ac.nz> <768@dgis.dtic.dla.mil> <8457@sybase.sybase.com>
Organization: Defense Technical Information Center (DTIC), Alexandria VA
Lines: 29

tim@ohday.sybase.com (Tim Wood) writes:

>One can index BLOBs ...  by maintaining an identifier column value
>of a simple datatype for each row containing a BLOB.  The indexing 
>on the simple datatype is bound to be faster and more reliable than
>the one-off indexing code a user writes for his/her BLOB datatype.

I can show counterexamples (they happen to be textual datatypes).
So it's not "bound to be".  Might be on average.  What it's bound to
be is more subvertible, less safe, less productive.  Simulated data
types are like that.

>Moreover, one can change the "ordering" of the BLOBs by changing 
>the identifier values, whereas with directly-indexed BLOBs one would need
>to change the type-specific indexing algorithm.  This amounts to changing 
>part of the datatype (or object type) definition.  

Sounds like a bad idea to me.  I prefer object ordering to be defined
by the object.  E.g. you mind if I change ordering of ints?  Say by one 
application without other applications' knowledge?

Tim, it's strange to hear a Sybase guy argue for moving functionality
from the database into the application.  You feeling ok?  :-)

-- Jon
-- 
Jonathan Krueger    jkrueger@dtic.dla.mil   uunet!dgis!jkrueger
The Philip Morris Companies, Inc: without question the strongest
and best argument for an anti-flag-waving amendment.