Monday, March 5, 2012

Optimized Master Detail relationships with DQM, not really

Here's an extract from IBM site on optimized master detail relationship using DQM (http://publib.boulder.ibm.com/infocenter/cbi/v10r1m0/index.jsp?topic=%2Fcom.ibm.swg.ba.cognos.dyn_query.10.1.0.1.doc%2Fc_master-detail.html):

Optimized master detail relationships in reports

Master detail relationships allow you to deliver information that would otherwise require two or more reports.

You specify a relationship between the query in the master data container and the query in the detail data container. For example, you can combine a master list with a detail chart. The list can contain product lines and the chart can show details for each product line.

With the dynamic query mode, master detail relationships are optimized. IBM® Cognos® pushes the master query as a separate edge to the detail query. Therefore, instead of sending one detail query to the data source for each master value, only one query is sent for HTML, PDF, and Microsoft Excel spreadsheet software output formats.
That is not the case though when you check the profile tree logs. Master detail relationships, still execute the old fashioned way with DQM. I had this confirmed by IBM as well that this is as per design.
I am posting this so developers don't get misleaded by the article. Wish IBM removes the misleading article.