how to integrate kdb/q with BI tools like cognos to create visualizations and graphs. I have some historical data in KDB database and i want to plot trends using cognos BI tools?
There's no out-of-the box way of doing this as you won't be able to use the normal database connectors that come with these types of BI tools (they would have ODBC, etc). A very hairy option is simply to batch up a copy of the data in KDB to an SQL database that Cognos understands. Obvious disadvantages there.
I don't really know much about Cognos, but there seems to be some plugin development in the applications - maybe you can use the c# or c++ api to kdb to pass data along to the BI application.
EDIT
panopticon.com have some really funky data visualisations, if that's all you want.. Saw a demo once, very cool.
EDIT 2
I really should read questions more thoroughly :) Re trends, why not simply use R or the very many graphing applications for which you can have C# plugins? With R trending etc becomes an easy process. If you prefer Excel, you can interface with KDB directly (http://code.kx.com/q/interfaces/excel-client-for-q/)