Oracle-L: RE: Warehouse design: snowflake vs star schemas

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Mon, 14 Oct 2002 06:08:34 -0800
Message-ID: <F001.004E7F38.20021014060834@fatcity.com>

Peter - What does this article have to do with snowflake vs. star schema? I didn't see where Chris Date was advocating snowflaking.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Monday, October 14, 2002 4:59 AM
To: Multiple recipients of list ORACLE-L

Just for the record (and perhaps to confirm that there are always two sides to a story). Readers may like to see the article Chris Date wrote to Ralph Kemball on the subject of business rules and integrity constraints:

http://www.dbdebunk.com/kimball1.htm

peter
edinburgh

> -----Original Message-----
> From: Alexandre Gorbatchev [mailto:alexandre.gorbatchev_at_avermann.de]
> Sent: 09 October 2002 15:04
> To: Multiple recipients of list ORACLE-L
> Subject: RE: Warehouse design: snowflake vs star schemas
>
>
> Dennis,
>
> Thanks for the link. It's a great DW resource.
> There are not only fundamentals, but some valuable real-life
> stuff, which is
> what I need. Live and learn, learn,learn...
>
> Regards,
> Alex
>
> -----Original Message-----
> WILLIAMS
> Sent: Tuesday, October 08, 2002 7:39 PM
> To: Multiple recipients of list ORACLE-L
>
>
> Alexandre
> Stephane gave you an excellent reply. If you want to learn
> more about
> these DW design issues, I would start by visiting
> http://www.ralphkimball.com. He is one of the leading figures
> in the DW
> field, and has copies of all his articles posted on his site.
> I would start
> with the oldest articles because those are where he discusses the
> fundamentals of data warehousing.
>
>
> Dennis Williams
> DBA
> Lifetouch, Inc.
> dwilliams_at_lifetouch.com
>
> -----Original Message-----
> Sent: Tuesday, October 08, 2002 3:29 AM
> To: Multiple recipients of list ORACLE-L
>
>
> Stéphane,
>
> Thanks for response.
>
> > I have always discplined myself to use star schema and
> > never snowflake.
> Would you mind asking why?
>
> > The "Which one is easier to implement and easier ETL
> > ?" is not a good question as your data model should
> > not be design for the ETL procecess but only for the
> > querying.
> I mean ETL to load data _INTO_ data warehouse. Of course,
> complexity is
> mostly determined by sources, but still I'd like to know if
> there is any
> general influence by DW's data model.
>
> Another question. Is it feasible to make date dimension or
> just use date
> column? For example, Oracle Discoverer can work with date
> columns using
> hierarchies Y->M->D and similar.
> What is faster: separate table for date dimension or date column?
> If I go with date dimension table should I use date column as
> a foreign key
> in fact table or use some artificial key?
>
> TIA,
> Alexandre
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Alexandre Gorbatchev
> INET: alexandre.gorbatchev_at_avermann.de
>
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> Author: Alexandre Gorbatchev
> INET: alexandre.gorbatchev_at_avermann.de
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Received on Mon Oct 14 2002 - 09:08:34 CDT