BIDs uses a data cache when designing Reporting Services reports to speed up your development. Long round trips for parameters and data are eliminated, improving your design-peview-design-preview iterations. That’s speedy.
But if the data changes on the back-end and you really want to see it, you might be in for a disappointment. Worse, new SSRS report developers who are unaware of this feature might pull their hair out while trying to troubleshoot data that either doesn’t match a production report run or the back-end data source.
I happen to like the feature for quick report development. But if you don’t, short of pressing “refresh” during each report preview, you can turn this off.
Find your config file that controls the Report Designer in BIDS. For SQL Server 2008 SSRS, this should be:
C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies\RSReportDesigner.config
Change CacheDataForPreview to “false”