I am helping out some very advanced Business Objects Users that have used Derived Tables and Aggregate Awareness A LOT in their Universes. They are now wanting to test the waters with Cognos 8. I am not aware of these two features being available within Framework Manager... Can any of you shine some light on this? I am sure I am not the first to ask this... ::)
Search feature is awesome... But I still need help with combatting Aggregate Awareness.
Quote from: blom0344 on 29 Jan 2010 04:11:36 PM
It need not be database views. AFAIK you can pretty much build them as SQL query subjects in the FM model. We call them 'Cognos views'.
For the query optimizer it should not matter.
The competition (Business Objects) calls these 'derived tables' and these also only exist in the metadatalayer.
Cognos tries to make a point with proper modelling generating optimized SQL. Unless you are using a very ideal starschema to work against I feel that database views or Cognos SQL query subjects are a great way to provide flexibility in the transformation layer.
Cognos 8 does not have the equivalent of BO's aggregate awareness. In recent years RDBMS vendors have taken up the task to enable aggregate awareness through RDBMS views (indexed views;materialized views; AST (automatic summary tables) and such)
The downside is that you need to rely on the query optimizer to do a rewrite to the aggregate. you cannot enforce it through Cognos8 (like you can with BO). This is probably one of the few areas where BO outdoes Cognos8..
I figured as such, but needed the official stamp of approval. Thank you for the help.