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Report Dataware house aggregation of defects and test cases/script

Accepted answer

You should check out RRDI or Insight for such kind of reports. Cross-application links are not exposed to BIRT.
Comments

And RRDI will only apply when applications share a Jazz Team Server.

Can i export the created reports to publish them on the jazz web server ? Maybe as a widget or in the reporting view?

Yes, you can read more details there:

Thanks for your further information. Do i really need to install a RRDI Server? I just want to create a Report which should be imported into the Jazz Team Server... (http://pic.dhe.ibm.com/infocenter/clmhelp/v3r0m1/index.jsp?topic=%2Fcom.ibm.rational.rcpr.help.doc%2Ftopics%2Ft_setup_live_reporting.html)

Yes, to author the report you need to install RRDI.