Generate hierarchical path
See if this helps.

SQL&gt; select ltrim(sys_connect_by_path(classificationid, ' \ '), ' \ ') hierarchypath
  2  from classstructure
  3  where parent is not null
  4  connect by prior classstructureid = parent
  5  start with parent is null;

HIERARCHYPATH
--------------------------------------------------------------------------------
FLEET \ LIGHTDUTYVEHICLE
FLEET \ MEDIUMDUTYVEHICLE
ACTIVETRANSPORTATION \ FACILITYWALKWAY
ACTIVETRANSPORTATION \ TRAIL
ACTIVETRANSPORTATION \ SIDEWALK
ACTIVETRANSPORTATION \ SIDEWALK \ SDWRAMP

6 rows selected.

SQL&gt;