When importing INTERLIS data you cannot select objects on the layer vw_tww_wastewater_structure and symbols are not displayed correctly:

The following query needs to be applied to set a main_cover:

UPDATE tww_od.wastewater_structure WS SET fk_main_cover = structure_cover.co_obj_id FROM ( SELECT WS.obj_id AS obj_id, min(CO.obj_id) AS co_obj_id FROM tww_od.wastewater_structure WS LEFT JOIN tww_od.structure_part SP ON SP.fk_wastewater_structure = WS.obj_id LEFT JOIN tww_od.cover CO ON SP.obj_id = CO.obj_id GROUP BY WS.obj_id ) AS structure_cover WHERE structure_cover.obj_id = WS.obj_id;

@ponceta To discuss in technial group tomorrow how to add this. Also discuss if query update_mainnode is also necessary or not.