Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Fact/Dimension - for DW and also DM?

Posted on 2011-02-17
9
Medium Priority
?
588 Views
Last Modified: 2012-05-11
is the Fact/Dimension way of building database only for Data warehouse or Data Mart also has the same concept?

thanks
0
Comment
Question by:anushahanna
  • 4
  • 3
9 Comments
 
LVL 17

Assisted Solution

by:MIKE
MIKE earned 300 total points
ID: 34923676
No

Fact/Dimensions are more based on the KIMBALL methodology, a Data Mart is more inline with INMON methodology.

Basically KIMBALL believes that it is better to build the DATA WAREHOUSE first based on Business Processes and requirements, INMON believes that the DATA MARTS should be build first based on Business Processes/Requirements, then the DW should be based on these data marts.

KIMBALL METHOD = Fact / Dimensions (star schema)
INMON METHOD = DATA MART based on business units/processes.

In my opinion, KIMBALL approach is the more practical way of building Enterprise DW's.

However, the debate is a never-ending one.....

0
 
LVL 6

Author Comment

by:anushahanna
ID: 34935918
>>INMON ......then the DW should be based on these data marts.

what specific methodology?

regardless, in both cases, DW ends up with Facts/Dim?
0
 
LVL 22

Accepted Solution

by:
dportas earned 1700 total points
ID: 35016949
CRXIuser2005 seems to have his summary of the Ralph Kimball and Bill Inmon approaches the wrong way round.

Kimball's approach is to create data marts. Kimball's view is that a "data warehouse" is nothing more or less than a collection of marts. Kimball's "dimensional" modelling approach is therefore the one he recommends only for building marts. Marts are what dimensional modelling is typically used for. Inmon's approach is to build a DW first and then use that to populate marts. A DW typically uses a Normal Form rather than dimensional approach.

In general in my experience (and as recommended by Bill Inmon) the most successful way to build a data warehouse is a Normal Form design (I suggest at least Boyce Codd / 5th Normal Form). "Dimensional" modelling approaches can work acceptably for simple models with a few dimensions. You could use a dimensional approach to build a large enterprise warehouse but almost by definition it makes the model and the load process much more complex than they need to be. Large dimensional models are very difficult to maintain and refactor and cause significant problems and costs due to the large amount of redundant data they create.

Whereas dimensional models were popular 10 years ago it's fair to say that they are much less so today because its drawbacks are much more apparent and relevant today than they were in the past. My suggestion would be that you consider a Normal Form approach rather than a dimensional one for your DW.

0
Free learning courses: Active Directory Deep Dive

Get a firm grasp on your IT environment when you learn Active Directory best practices with Veeam! Watch all, or choose any amount, of this three-part webinar series to improve your skills. From the basics to virtualization and backup, we got you covered.

 
LVL 6

Author Comment

by:anushahanna
ID: 35082579
thanks dportas

>>I suggest at least Boyce Codd / 5th Normal Form

isn't that the max?

>>My suggestion would be that you consider a Normal Form

so that would be like OLTP method, right?
0
 
LVL 22

Assisted Solution

by:dportas
dportas earned 1700 total points
ID: 35197221
>> isn't that the max?
5NF eliminates all join dependencies except those implied by superkeys. 6NF and DKNF are somewhat "stricter" though they are less commonly applied.

>> so that would be like OLTP method, right?
Normal Form is a good guiding principle for any type of database workload, yes.
0
 
LVL 6

Author Comment

by:anushahanna
ID: 35204013
Thanks for clarifying that, dportas.

what is a dependable reference you use for Bill Inmon method of normal form design?
0
 
LVL 22

Assisted Solution

by:dportas
dportas earned 1700 total points
ID: 35204640
Normal Form wasn't invented by Inmon and isn't really a topic in his books but take a look at:

www.inmoncif.com
www.amazon.com/gp/aw/d/0764599445
0
 
LVL 6

Author Comment

by:anushahanna
ID: 35206555
helped - thanks very much!
0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

It is possible to export the data of a SQL Table in SSMS and generate INSERT statements. It's neatly tucked away in the generate scripts option of a database.
Lotus Notes has been used since a very long time as an e-mail client and is very popular because of it's unmatched security. In this article we are going to learn about  RRV Bucket corruption and understand various methods to Fix "RRV Bucket Corrupt…
Using examples as well as descriptions, and references to Books Online, show the documentation available for datatypes, explain the available data types and show how data can be passed into and out of variables.
Viewers will learn how to use the INSERT statement to insert data into their tables. It will also introduce the NULL statement, to show them what happens when no value is giving for any given column.

971 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question