Hello, Srini
Thank you for contacting us regarding your question.
At the moment this feature works only with databases localhost.
In MySQL there is not only a base wp, there can be as many as you like. If you select external db, then specifying the database name and password/ login, you can connect to it and select its tables.
In the next release, we’ll add the connectivity to the external database.
Best regards,
https://supsystic.com
Ole