provide wrapper function for DROP TABLE

Use psycopg2 formatting to ensure correct quoting.

nominatim/tools/exec_utils.py

@@ -141,6 +141,6 @@ def get_url(url):
     try:
         with urlrequest.urlopen(urlrequest.Request(url, headers=headers)) as response:
             return response.read().decode('utf-8')
-    except:
+    except Exception:
         LOG.fatal('Failed to load URL: %s', url)
         raise

nominatim/tools/freeze.py

@@ -29,7 +29,7 @@ def drop_update_tables(conn):
         tables = [r[0] for r in cur]
 
         for table in tables:
-            cur.execute('DROP TABLE IF EXISTS "{}" CASCADE'.format(table))
+            cur.drop_table(table, cascade=True)
 
     conn.commit()
 

nominatim/tools/refresh.py

@@ -49,7 +49,7 @@ def load_address_levels(conn, table, levels):
         _add_address_level_rows_from_entry(rows, entry)
 
     with conn.cursor() as cur:
-        cur.execute('DROP TABLE IF EXISTS {}'.format(table))
+        cur.drop_table(table)
 
         cur.execute("""CREATE TABLE {} (country_code varchar(2),
                                         class TEXT,

nominatim/tools/special_phrases/sp_importer.py

@@ -248,20 +248,14 @@ class SPImporter():
             Delete the place_classtype tables.
         """
         LOG.warning('Cleaning database...')
-        # Array containing all queries to execute.
-        # Contains tuples of format (query, parameters)
-        queries_parameters = []
 
         # Delete place_classtype tables corresponding to class/type which
         # are not on the wiki anymore.
-        for table in self.table_phrases_to_delete:
-            self.statistics_handler.notify_one_table_deleted()
-            query = SQL('DROP TABLE IF EXISTS {}').format(Identifier(table))
-            queries_parameters.append((query, ()))
-
         with self.db_connection.cursor() as db_cursor:
-            for query, parameters in queries_parameters:
-                db_cursor.execute(query, parameters)
+            for table in self.table_phrases_to_delete:
+                self.statistics_handler.notify_one_table_deleted()
+                db_cursor.drop_table(table)
+
 
     def _convert_php_settings_if_needed(self, file_path):
         """