Users can access database connections assigned to them or to groups to which they belong.
When documents are assigned to groups, the database connections that the document uses must also be assigned to the groups. Otherwise, group members can access the document, but not its data values (unless they are granted individual user access).
To mitigate the risk of conflicting permissions, store documents and their database connections in the same folders. Whenever possible, distribute documents and database connections to groups. It is easier to set permissions for all files in a folder and all users in a group than to manage permissions for individual files and users.