Subject Area's are just objects within On Demand. Are you planning to connect to the CRM using OBIEE?
To Create the Joins you will need to base this on the External ID's of the object as long as this information is the same within On Demand and your source system that you are using OBIEE to report off.
Thanks for your reply
I am not going to use OBIEE at all as my source..I just want to compare OBIEE and Oracle CRM on demand.
As creating dashboards and Reports in Oracle CRM on demand is similar to creating reports and dashboards in OBIEE.
Please can you give me any document or URL for same.