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IBM Cognos 8 Platform => COGNOS 8 => BI Modeling (Transformer) => Topic started by: actcognosuser on 07 May 2010 07:45:19 AM

Title: Building a cube vs DW?
Post by: actcognosuser on 07 May 2010 07:45:19 AM
Hi All,
             I have a question about building cubes.For cognos there is transformer to build cubes.Can we build a cube directly from database.(like Oracle or db2?).

Or do we actually need to go through the tool provided by the vendor?

Cubes can be built off a DW.But what is d difference betwn a DW and a cube.Can it be an option to use a cube instead of a DW?
Title: Re: Building a cube vs DW?
Post by: MFGF on 07 May 2010 08:14:07 AM
Cubes are typically summarized, whereas a data warehouse is usually expected to support a more detailed level of data.  Warehouses usually also preserve history, and span the entire Enterprise whereas cubes can be more focused.
Title: Re: Building a cube vs DW?
Post by: actcognosuser on 07 May 2010 08:54:33 AM
Thanks for ur response MFGF. If I need to build a cube do i have to go with any of the vendor specific tools
or is it possible to build one directly from a database.

also is a dw metadata or does it contain  actual data like the cube?
Title: Re: Building a cube vs DW?
Post by: MFGF on 07 May 2010 10:11:30 AM
Use the appropriate cube building tool to create the desired cube.  For example, you will need Transformer in order to create a PowerCube.

I assume that when you refer to a data warehouse, you are thinking of the Presentation Layer, where the reporting data is stored in a form that is fast and easy to report from.  It is usually just a collection of interconnected database tables and/or views, often in the form of star schemas, but it does contain the actual reporting data.

MF.
Title: Re: Building a cube vs DW?
Post by: actcognosuser on 10 May 2010 08:15:56 AM
is cube a concept or is it tool specific???
Title: Re: Building a cube vs DW?
Post by: cognostechie on 10 May 2010 06:19:27 PM
A Cube is a physical object that contains data inside it in a multi-dimensional form. In case of Cognos Poercube , it is an ascii file that contains data inside it. In case of other cubes like SAP BI, it is a collection of tables inside a database which again stores data inside it. Yes, it is tool specific.

I would suggest browse the internet to get the basic idea about what is a cube and what is a DW. There are some databases that have their own cube building tools.