Databases can be added by Admins from the Advanced page.
Specify an identifiable name of the database, such as “Business Data” or “Client Data” etc. This will be used to reference this databases later.
The Connection String will determine how to connect to the database. Since the Connection String may have sensitive info in it, it is omitted when selecting databases, instead AutoDocument references each by the Name you supply.
So far the supported databases are: MySQL (and MariaDb), PostgreSQL, Microsoft SQL Server and SQLite.
See this great resource for Connection String Options depending on your individual database setup.