fix _create_sql_stmt

Signed-off-by: Sebastian Schüpbach <sebastian.schuepbach@unibas.ch>

mediametadatatodb_app/resources/MediametadataToDB.py

@@ -88,14 +88,13 @@ def _get_values_from_digital_object(msg):
 
 
 def _create_sql_stmt(table_name, record, fields):
-    (db_fields, db_values) = [(dbField, record[dbField])
-                              for dbField in fields
-                              if dbField in record and record[dbField] is not None]
+    db_fields = [dbField for dbField in fields
+                 if dbField in record and record[dbField] is not None]
+    db_values = ','.join([str(record[db_field])
+                          if isinstance(record[db_field], numbers.Number)
+                          else "'{}'".format(record[db_field])
+                          for db_field in db_fields])
     db_fields = ','.join(db_fields)
-    db_values = ','.join([str(db_value)
-                          if isinstance(db_value, numbers.Number)
-                          else "'{}'".format(db_value)
-                          for db_value in db_values])
     return 'INSERT IGNORE INTO {} ({}) VALUES ({})'.format(
         table_name, db_fields, db_values)