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.
[EMAIL PROTECTED]
-----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." <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
05/21/2002 05:48 PM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
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
[EMAIL PROTECTED]
-----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.
[EMAIL PROTECTED]
-----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 <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
05/20/2002 05:53 PM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L
<[EMAIL PROTECTED]>
cc:
Subject: Re: Data Warehouse experts, a simple question for
you
looks like published aug of 98 for that book?, like $60?
joe
[EMAIL PROTECTED] 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 <[EMAIL PROTECTED]>
>Sent by: [EMAIL PROTECTED]
>05/20/2002 04:08 PM
>Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L
<[EMAIL PROTECTED]>
> 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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