Can I change the datasource after a ssrs report is created?

Question

I need to change the DataSource for my SSRS reports. Some field names and DIM-FACT table names have changed on the SQL server 2008 database used to create SSRS reports. How can I change the DataSource do that without losing all of the work I have done? Some field names are not the same or have been removed. The reports were already uploaded/deployed from Visual Studio and copied to SharePoint 2010, Is there a way to modify the original datasource without having to rewrite the whole dril-down report? I am new to SSRS and I hope what I am asking makes sense )
Solution Explorer and Properties in Visual Studio where modified, but ReportData Section (on the left) are still the same. Can someone please help me?

Solution

In your example, you have your report splendidly broken out into 3 parts - an RDL, which is your actual Report definition; an RSD, which is your dataset, which houses a reference to a sproc or just your entire query, and maintains information about the field names, data types, etc; and an RDS, which is your datasource, and merely contains a connection string.

As long as the metadata between them remain the same, you can alter any of these files independently of the others - you can completely gut & rewrite your RSD, and as long as the field names, datatypes, and parameters are the same, the RDL will continue to work with no modifications needed. Similarly, you can change your datasource's (RDS) connection string, and as long as the new connection has access to the same objects, your RSD, and thus RDL will work fine.

So, if you merely need to change the data source, simply modify that file, and you're done.

It sounds, however, like you need to change your dataset. This can be as simple or as complicated as you'd like it to be. You could simply update your query, and alias all of the new field names back to what they were before your change. This would require no modifications to your RDL, though could be argued as being a bad practice.

Lastly, if this really is a simple change of replacing one value with another, know that all 3 files - RDS, RSD, RDL - are simply XML. Open them up using the Notepad clone of your choice, and do a find/replace for everything (you can also use "Code View" in Visual Studio).