1) cat_listing -
   id,
   title,
   listing_type_id (FK from `cat_listingtype`)

2) cat_listingtype -
   id,
   title

3) cat_listingsubtype -
   id,
   title

4) cat_typesubtype -
   id,
   type_id (FK from `cat_listingtype`)
   subtype_id (FK from `cat_listingsubtype`)