Display geometry data of a relation with PostGIS

Hi,

I am using OSM data in a postgreSQL/PostGIS database which i filled with osm2pgsql-tool.
So now i have the tables

planet_osm_point
planet_osm_line
planet_osm_roads
planet_osm_polygon

with geometry data and

planet_osm_nodes
planet_osm_ways
planet_osm_rels

with raw data.

How can I get an relation (e.g. Germany’s boundary) with all its geometry data?
I can easily load geometry data for this boundary from planet_osm_line (with a approximated bounding box around germany), but i can’t see the connection to the planet_osm_rels table.

Is there a way to get both tables “connected” (with sql)?

thanks so far!

Thorsten