At this time there is not a method to have the Tableau Server connect to the data directly. The data has to be published from Tableau Desktop to the Tableau Server to be accessible. Could it be possible to create a new data source withing Tableau Server? This would allow the creation of data sources where the databases reside behind a secure firewall (e.g. cloud-based server) where the Tableau Desktop may not have access to the data sources, but the Tableau Server does. Once the Tableau Server creates and stores the data sources, then multiple Tableau Desktops can access from the Tableau Server directly to create the views.