Oracle-L: RE: Data Warehouse experts, a simple question for you| Outdated?

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Wed, 22 May 2002 14:23:28 -0800
Message-ID: <F001.004686B4.20020522142328@fatcity.com>

Ian,

In the beginning was the data warehouse and yeah it was good. It would solve all corporate problems and would encompass all corporate data so all corporate minions would see the same data.
But yeah it took so long to create the corporate data warehouse that management despaired and canceled the project. Or by the time the monster data warehouse came blinking and straining into the daylight all the users said that the company had evolved in the meanwhile and the warehouse was obsolete.
So data warehouses gained a bad rep from corporate managers and yeah none would fain to propose the conception of a data warehouse for fear of castigation.
Then some marketing interns bribed a DBA to send them data weekly. And they stored this data in a database and lo, their superiors were impressed.
Everyone was in awe of the marketing database, but none dared tarnish it by speaking the name which shall not be mentioned, so it was christened a "data mart".
And lo, the data marts multiplied and were fruitful. And the DBA cursed the day she was weak and did give data to the marketing interns.
Then another prophet did arise and did challenge the prophet Kimball. His name was Inmon. And he did claim to be the progenitor of data warehouses. And therefore all should do data warehousing his way and use his terms.
And great confusion arose over the land. And many debates ensued, including some face to face between Inmon and Kimball. And terms such as Operational Data Store (ODS) were bandied about.
And some said that queries against the ODS were acceptable and others deemed them forbidden. And some said that if it looks like a data warehouse and smells like a data warehouse it verily indeed is a data warehouse.
And consultants warred against consultants and did call the other consultants ignoramuses in front of management such that nobody knew what anybody was talking about.
And the DBAs said that creating a data warehouse or data mart was not nearly as hard as figuring out what to call it.

The moral of the story is to figure out what you need to do and be aware that different authors use the same terms for different purposes and coin their own terms. Personally, I have understood everything that Kimball has written and have never been able to read one of Inmon's articles to the end. But maybe that is just me.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Wednesday, May 22, 2002 2:38 PM
To: Multiple recipients of list ORACLE-L Outdated?

Ian,

Good question. I think that I've seen more recenct references in articles that state the current thinking of DW/DM. I'm sure that I've seen Inmon refer to them that way, or maybe it was Richard Winter?

Anyway, I guess that part is a bit dated. There is so much good information
in that book though, that it's still worth its weight in gold. You won't find too many
publications for $60 that will take you step by step through building an entire
data warehouse, including the infrastructure.

Jared

"MacGregor, Ian A." <ian_at_SLAC.Stanford.EDU> Sent by: root_at_fatcity.com
05/21/2002 05:48 PM
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        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        RE: Data Warehouse experts, a simple question for

you| Outdated?

I am new to his books, three chapters in. The first release of the "Data Warehouse Toolkit" defines a data warehouse much as a data mart is today. Today we think of a data warehouse as having a highly normalized structure which stores information from various sources. We build data marts with structures optimized for querying; e.g., star schemas, from the warehouse. Kimball writes of the warehouse itself being based on a star schema.

The term data warehouse has not been immutable over the years. It was probably defined exactly as he has done when the book was first written. Do his new books redefine "data warehouse"?

Ian MacGregor
Stanford Linear Accelerator Center
ian_at_SLAC.Stanford.edu

-----Original Message-----
Sent: Tuesday, May 21, 2002 2:16 PM
To: Multiple recipients of list ORACLE-L

I second Jared's opinion. Ralph's books are clear and easy to read. This is
the fundamentals of data warehousing.
Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, May 21, 2002 2:30 PM
To: Multiple recipients of list ORACLE-L

Yup, $60, and worth every penny.

It may be 4 years old, but the information is still pertinent.

Jared

Joe Testa <jtesta_at_dmc-it.com>
Sent by: root_at_fatcity.com
05/20/2002 05:53 PM
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To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>

        cc: 
        Subject:        Re: Data Warehouse experts, a simple question for

you

looks like published aug of 98 for that book?, like $60?

joe

Jared.Still_at_radisys.com wrote:

>Joe,
>
>Add a generated PK to the time dimension. The PK is stored
>as an FK in the fact table.
>
>That way you can select from the time dimension by year, day, qtr,
>whatever,
>and easily pick out the correct fact table rows.
>
>"The Data Warehouse Lifecycle Toolkit" includes a spreadsheet to generate
>the DDL/DML for a very robust time dimension. I think it has about 20
>columns.
>
>Very good book, can't recommend it enough.
>
>Jared
>
>
>
>
>
>
>Joe Testa <jtesta_at_dmc-it.com>
>Sent by: root_at_fatcity.com
>05/20/2002 04:08 PM
>Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L
<ORACLE-L_at_fatcity.com>
> cc:
> Subject: Data Warehouse experts, a simple question for you
>
>
>Ok i'm messing with dimensions.
>
>dm_time to be exact:
>
>create table dm_time
>( calendar_date date not null,
> calendar_month number(2) not null,
> calendar_qtr number(1) not null,
> calendar_year number(4) not null);
>
>insert into dm_time values(to_date('20020101','YYYYMMDD'), 1,1,2002);
>insert into dm_time values(to_date('20030101','YYYYMMDD'), 1,1,2003);
>
> 2 rows nice and simple
>
> trying to validate the dimension comes up with an error, my guess is
>because of the design of the table
>
> where basically calendar_date is child of
> calendar_month is child of calendar_qtr is child of calendar_year,
>wont validate.
>
>- the question i have is this, should month really be like 2002-01 with
>the year included, likewise with qtr, then it
>will validate ok.
>
>Was the design of dm_time just dont wrong or am i missing something here.
>
>thanks, joe
>
>

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Author: Joe Testa
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Author: DENNIS WILLIAMS
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Author: MacGregor, Ian A.
  INET: ian_at_SLAC.Stanford.EDU

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  INET: Jared.Still_at_radisys.com

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  INET: DWILLIAMS_at_LIFETOUCH.COM

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Received on Wed May 22 2002 - 17:23:28 CDT