how to create star schema

[inu]

Hi
please guide me or refer me , how to create star schema model, without  this i cant create the package, and publish into the cognos 10 report studio.


Regards
inam

[Lynn]

I think the user guide is a good place to start. Although reading everything is a good idea, I'd point out the chapter on "Guidelines For Modeling Metadata" and "Modeling Relational Metadata" as particularly suited to your question.

Also, there is a board for Framework Manager which is a better place for you to post specific questions about using that tool.

http://pic.dhe.ibm.com/infocenter/caapps/v10r1m0/index.jsp?topic=%2Fcom.ibm.swg.im.cognos.ug_fm.10.1.0.doc%2Fug_fm.html

[TheCognosDave]

For a Star Schema all you need is 1 or more Dimension tables (i.e. DIM_PRODUCT) and one or more FACT tables (i.e. FACT_DAILY_SALES),

soooo

Create A Database ;-)

Then create tables in the database which represent the quantitative measurable data, typically by datetime (such as sales or other transactions) in your FACT_* tables and put the attributes you want to measure the data BY in your DIM_* tables (such as product or location)

and there's your Star Schema database.

Good Luck !  ;)

[inu]

Hi bro
How to make a table as fact or dimension, as far as know, if at least one column is having measure value i-e usage = fact. Then corresponding table is considered as fact table. Otherwise the table(Query Subject) is considered as dimension table.

   If not so, then please rectify it, if possible then please publish the screenshots of steps of creating star schema model, or please mail me at TheMuppetDeletedMyEmailAddress@WhereHasItGone.com

[Lynn]

Hi bro
How to make a table as fact or dimension, as far as know, if at least one column is having measure value i-e usage = fact. Then corresponding table is considered as fact table. Otherwise the table(Query Subject) is considered as dimension table.

   If not so, then please rectify it, if possible then please publish the screenshots of steps of creating star schema model, or please mail me at *************

I realize your response isn't directed to me, but I really think investing at least some time learning is a good idea. As good as this site is for helping people with Cognos it can't fully substitute for proper training and self-study.

Your assumption about how fact or dimension tables are identified is incorrect. You will find the answer in the opening pages of the chapter on "Guidelines for Modeling Metadata" where all the basic modeling concepts are explained. Below is the link for the PDF version of the guide in case that is preferable to the HTML version I posted earlier.

Also, I believe that posting email addresses is frowned upon so you should consider editing the post to remove yours. Personal messaging within the site allows people to contact each other directly. Mainly the idea is that we are a community so posting information to benefit everyone is a good goal.

http://download.boulder.ibm.com/ibmdl/pub/software/data/cognos/documentation/docs/en/10.1.0/ug_fm.pdf

[TheCognosDave]

holy cats that pdf is 607 pages !  I'm definitely not an expert on all of that, but it sounds like Lynn has read it backwards and forewords ;)

inamulhaque:

I think you're close, but unfortunately without a lot more context I don't think I can easily point you in the right direction.  If you're very new to working with databases, then the term "star schema" probably adds confusion.  This is not a "Cognos specific" data model design concept.  It refers to a methodology of designing tables in a database to support your reporting needs.

I would recommend this...

1) Determine what database you are running on and what access you have to it, and what tools you need to access it.
2) Determine what existing tables you are reporting from, and the relationships of the data in the tables.
3) Head to your local bookstore and buy a good data modelling book like "Star Schema The Complete Reference".
4) Model your reporting database using the star schema design concepts  ;)

Good Luck inamulhaque !

[MFGF]

Hi bro
How to make a table as fact or dimension, as far as know, if at least one column is having measure value i-e usage = fact. Then corresponding table is considered as fact table. Otherwise the table(Query Subject) is considered as dimension table.

   If not so, then please rectify it, if possible then please publish the screenshots of steps of creating star schema model, or please mail me at TheMuppetDeletedMyEmailAddress@WhereHasItGone.com

I posted recently about how query subjects are identiified as Fact or Dimension based on relationship cardinalities. If it helps, the post is here:

http://www.cognoise.com/index.php/topic,22553.msg69336.html#msg69336

Cheers!

MF.