I wanted to integrate cognos and fetch the reports in pdf/chart format from cognos server. I have not worked much on cognos framework.
I have checked other question also for the same but not got any proper answer to this question.
Please help!
There are a handful of APIs for orchestrating activities or retrieving data in Cognos.
Based on the specific use case you're citing, I'd lean towards the URL interface (item #1 below).
Here's an article which describes Cognos Mashup vs. Cognos SDK, and provides some heuristics for when you would choose one over the other :
http://www.motio.com/blog/2010/11/01/cognos-sdk-vs-cognos-mashup.do