You cannot switch data source types. For example, Tableau will not change from Oracle to PostgresSQL, or from SQL Server to Microsoft Access.
Please go through links it will help you.
Hi, this is not necessarily that easy to do directly on the data source.
This is how I normally to this:
Right click on the data source in Desktop, "Create Local Copy". Go to that location on your disk where you saved the local copy, open the archive in win-zip/z-zip or similar, choose edit. Then the data source can be opened in notepad or similar. Do a Find/Replace on your existing data source to replace with your new one.
Remember to replace database name, server, username etc.
Close the file and save.
Reopen the original workbook, go to File, Open and find the local copy you've just changed.
IMPORTANT: I've found that if you open up all dashboards & sheets before you do a "Replace data source", this will then make sure that you keep all formatting, filters and colors that you've might have changed!
Check that all dimensions and measures are being replaced and double check your dashboards before you save/publish your workbook - now with a new source.
Hope this helps!