MPIIDs are not suitable for a dimensinon because of their high cardinality - you're better off using SQL.

My understanding is that direct database access to the edge gateway is not supported, but you'd have to confirm that with the HSIE team.

While you can use %HSAA_* roles to control the functionality available to a  user, there is no way to restrict what particular data a user sees.  

DeepSee has a REST interface, but I don't know the state of any Tableau integration.

Ponnumani - see the Health Insight User Guide (in the /csp/docbook/DocBook.UI.Page.cls?KEY=HSAA in your HealthShare installation) for some examples - Topher