Add default tuple adapter (#372)

Author: sitingren

vertica_python/tests/unit_tests/test_sql_literal.py

@@ -14,6 +14,7 @@
 
 from __future__ import print_function, division, absolute_import
 
+from collections import namedtuple
 from decimal import Decimal
 from uuid import UUID
 import datetime
@@ -48,6 +49,14 @@ def test_default_adapters(self):
         # String
         self.assertEqual(cursor.object_to_sql_literal(u"string'1"), "'string''1'")
         self.assertEqual(cursor.object_to_sql_literal(b"string'1"), "'string''1'")
+        # Tuple and namedtuple
+        self.assertEqual(cursor.object_to_sql_literal(
+            (123, u"string'1", None)), "(123,'string''1',NULL)")
+        self.assertEqual(cursor.object_to_sql_literal(
+            ((1, u"a"), (2, u"b"), (3, u"c"))), "((1,'a'),(2,'b'),(3,'c'))")
+        Point = namedtuple('Point', ['x', 'y', 'z'])
+        p = Point(x=11, y=22, z=33)
+        self.assertEqual(cursor.object_to_sql_literal(p), "(11,22,33)")
 
     def test_register_adapters(self):
         class Point(object):

vertica_python/vertica/cursor.py

@@ -519,6 +519,11 @@ def object_to_string(self, py_obj, is_copy_data):
             return self.format_quote(as_text(py_obj), is_copy_data)
         elif isinstance(py_obj, (integer_types, float, Decimal)):
             return str(py_obj)
+        elif isinstance(py_obj, tuple):  # tuple and namedtuple
+            elements = [None] * len(py_obj)
+            for i in range(len(py_obj)):
+                elements[i] = self.object_to_string(py_obj[i], is_copy_data)
+            return "(" + ",".join(elements) + ")"
         elif isinstance(py_obj, (datetime.datetime, datetime.date, datetime.time, UUID)):
             return self.format_quote(as_text(str(py_obj)), is_copy_data)
         else: