Crystal Report - Map Field

Hi,
I had designed the crystal reports with the SQL command as the data source. Now I have created views with the same command with some modifications. I use the "Set DataSource Location" to change the data source to the created view. When i click update, I get the Map Dialog.
I'm fine with all these things. My problem is, if i had left some fields unmapped and saved the report, I'm unable to map further.Also I'm not able to change my mapping later. How to go about it? Is there a way to change the mappings?

Regards,
- KulanthaivelDo verify Database that will show the mappings if any