[thelist] Database Design Question

[Luther, Ron]

Joshua Olson noted:

>>You're two examples are typical OLAP solutions.  It's common practice
to
>>translate data that is optimized for Transactions (OLTP) into a form
that
>>is optimized for reporting (OLAP).


Hi Joshua!


Guilty as charged!  ;-)

Yes. I'm familiar with OLTP and OLAP. I spend a fair amount of time
these
days mangling OLTP-sourced data into OLAP applications.

{Sorry. Didn't mean to muddy up the waters. Just looking at the two
mails
I replied to it looked as though they were discussing a 'general case'
situation.}

>>http://www.sqlsquare.com/viewtip.asp?tipid=2

Nice, succinct summation ... and a good reminder!

>>As a rule of thumb, do not represent the same data twice in a single
>>database.  Keeping detailed records plus summary records would be a
>>violation of this rule of thumb.

... for OLTP systems naturally.  In an OLAP setting 'denormalization'
is quite desirable.


[Hey Joshua,

I'm pretty sure you have a good idea how _many_ projects (particularly
of the sort run into by a fairly large percentage of our members here)
waffle back and forth ...

* Client wants a shopping cart system.
* Then client wants reporting; inventory, backlog, product line stats,
etc.
* Then client wants cart modified to accumulate more data.

Those kinds of situations can make it pretty easy, for a lot of folks
to forget the sharp difference between OLTP and OLAP and try building
'blended' solutions.

I AGREE! ... it's a 'bad idea' (TM).

{And I'm also familiar with (and agree with) the stories of the DBAs who
were fired for indexing the OLTP systems to speed up reporting.)  ;-)

Any interest in writing or collaborating on an evolt article on tips
to help folks in the trenches keep this straight?]


RonL.