Some examples of service endpoints currently available through extensions are: For information about creating your own custom extensions, see Overview of extensions for VSTS.
You can control who can define new service endpoints in a library, and who can use an existing service endpoint.
The validation link uses a REST call to the external service with the information you entered, and indicates if the call succeeded. Selecting an existing subscription automatically creates a new Azure service principal that is assigned the Contributor role and so, by default, has access to all resources within the subscription.
Defines and secures a connection to a Microsoft Azure subscription using Azure credentials or an Azure management certificate. To maximize security when using this connection approach: How do I create a new service endpoint?
You will typically use an existing service principal that has restricted scope.
You can allocate service principal permissions at the subscription level, resource group level, or resource level.
By default, project contributors are added as members of this group.
Along with this, as your applications become more and more complex you will probably not want to rely on Visual Basic's data controls, but instead use the ADO objects directly. The concept behind Visual Basic ADO was Universal Data Access (UDA), where one database access method could be used for any data source; it was designed to replace both DAO and RDO.
You can define endpoints in Visual Studio Team Services (VSTS) or Team Foundation Server (TFS) that are available for use in all your tasks.