Fix City.each_within_poly()

lib/xmet/city.py

@@ -1,14 +1,14 @@
 import csv
 import shapely
 
-from xmet.db    import Database
+from xmet.db    import Database, DatabaseTable, DatabaseOrder
 from xmet.coord import COORD_SYSTEM
 
 """
 Implements a parser and wrapper class for a TSV list of cities.
 """
 
-class City():
+class City(DatabaseTable):
     __slots__ = (
         'id', 'name', 'state', 'population', 'location'
     )
@@ -65,19 +65,12 @@ class City():
 
     @staticmethod
     def each_within_poly(db: Database, poly: shapely.Polygon):
-        sql = """
-            select
-                *
-            from
-                xmet_city
-            where
-                ST_Within(location, GeomFromText(:poly, 4326)) = 1
-            order by
-                population desc
-        """
-
-        st = db.query_sql(City, sql, {
+        st = db.query(City, [
+            'ST_Within(location, GeomFromText(:poly, 4326)) = 1'
+        ], {
             'poly': shapely.to_wkt(poly)
-        })
+        }, [
+            ('population', DatabaseOrder.DESC)
+        ])
 
         yield from st.each()