Can you use connections to tabels from local databases for the data models?

I am aware of three ways to include data models: include the local files, upload data in the ARIES server cluster (and use those through the 'urn'), or use external WF/CS. However, we have virtually all of our spatial data in spatial databases (PostGIS) on local networks (without any WF/CS).

I could either dump these tables as shapefiles or upload them into the ARIES server cluster, however, this looks inefficient from several perspectives (e.g. data duplication, work). Moreover, some of these tables (e.g. the detailed road network) are pretty large.

Is there an easier and more direct solution to access these data (e.g. through the 'dsn'), or would I have to set up a WFS?

Thanks a lot!