Database View vs. Dimensional View

[ratnalein]

Hallo everyone,

as fas as I know, in Framework Manager, the first step to build our data model:
to build the database view. To be concrete, in this step, we are giving the informations regarding the relationships and cardinalities from our tables.

In the second step:
to build the dimensional view. Here, we are building the hierarchies and levels needed.

I would like to understand whether cognos builds MOLAP(to build a real multi dimensional OLAP store structures) in the dimensional view? Or would cognos build an OLAP on the fly for the queries?

Thank you very much for the comments.

Regards,
Ratna

[tjohnson3050]

Cognos doesn't do MOLAP in Framework Manager, only ROLAP.   Traditional cubes are built using Transformer and in memory cubes are built with TM1.

[cognostechie]

Just to add to what tjohnson said - The dimensional view defined in Framework Manager will build an OLAP on the fly for the queries. Everything in Framework Manager is virtual, nothing physical. Transformer will build a physical MOLAP whereas TM1 will build a physical ROLAP. The in-memory cube built by TM1 physically resides in a database and gets loaded in the memory for execution

[ratnalein]

Thank you for the clear answers...

[MFGF]

Just to add another option, Dynamic Cubes in 10.2 give you another choice - here Cognos 10 has ROLAP support and aggregate awareness. There are some important guidelines on how the underlying data should be structured - either as Star or Snowflake schemas - but it's another weapon in your Cognos arsenal :)

MF.