SharePoint 2010 Excel Web Access Web Part

I have questions about the Excel Web Access Web Part in SharePoint 2010:

1. When I edit it in the Web Part, does it only edit the spreadsheet in the Shared Documents (if it was uploaded there) or is there a way to also replicate/keep the data in the SharePoint database?

2. is there a way to consolidate the multiple spreadsheets into one Web Part?

3. Is there a way to automate the spreadsheet import?

Thank you.