How to change the datasource of Crystal Reports Programmatically?

[gyaja]

This is a Crystal Reports XI R2 Question:
I have a large no. of Crystal Reports which are designed by directly connecting to the Database rather than using ADO.NET or XML Datasource.

I want to change the datasource of the reports at the runtime, primarily bind the report with Dataset rather than supplying logon info content to avoid multiple calls to the database while navigating across pages.
The issue with connecting to database is, for each page navigation, it is connecting to the database and executing the stored procedure which is the source of data for the reports.

Thanks in advance,
- gyaja