refs #21199. to_sql() support passing a callable to method parameter.

Author: schettino72

pandas/io/sql.py

@@ -8,6 +8,7 @@
 from datetime import datetime, date, time
 import csv
 from io import StringIO
+from functools import partial
 
 import warnings
 import re
@@ -660,8 +661,9 @@ def insert(self, chunksize=None, method=None):
             exec_insert = self._execute_insert_multi
         elif method == 'copy':
             exec_insert = self._execute_insert_copy
+        elif callable(method):
+            exec_insert = partial(method, self)
         else:
-            # TODO: support callables?
             raise ValueError('Invalid parameter `method`: {}'.format(method))
 
         keys, data_list = self.insert_data()

pandas/tests/io/test_sql.py

@@ -435,6 +435,25 @@ def _to_sql_append(self):
         assert num_rows == num_entries
         self.drop_table('test_frame1')
 
+    def _to_sql_method_callable(self):
+        check = []  # used to double check function below is really being used
+
+        def sample(pd_table, conn, keys, data_iter):
+            check.append(1)
+            data = [{k: v for k, v in zip(keys, row)} for row in data_iter]
+            conn.execute(pd_table.table.insert(), data)
+        self.drop_table('test_frame1')
+
+        self.pandasSQL.to_sql(self.test_frame1, 'test_frame1', method=sample)
+        assert self.pandasSQL.has_table('test_frame1')
+
+        assert check == [1]
+        num_entries = len(self.test_frame1)
+        num_rows = self._count_rows('test_frame1')
+        assert num_rows == num_entries
+        # Nuke table
+        self.drop_table('test_frame1')
+
     def _roundtrip(self):
         self.drop_table('test_frame_roundtrip')
         self.pandasSQL.to_sql(self.test_frame1, 'test_frame_roundtrip')
@@ -1211,6 +1230,9 @@ def test_to_sql_append(self):
     def test_to_sql_method_multi(self):
         self._to_sql(method='multi')
 
+    def test_to_sql_method_callable(self):
+        self._to_sql_method_callable()
+
     def test_create_table(self):
         temp_conn = self.connect()
         temp_frame = DataFrame(
@@ -1686,7 +1708,6 @@ class _TestSQLiteAlchemy(object):
 
     """
     flavor = 'sqlite'
-    supports_multivalues_insert = True
 
     @classmethod
     def connect(cls):
@@ -1735,7 +1756,6 @@ class _TestMySQLAlchemy(object):
 
     """
     flavor = 'mysql'
-    supports_multivalues_insert = True
 
     @classmethod
     def connect(cls):
@@ -1805,7 +1825,6 @@ class _TestPostgreSQLAlchemy(object):
 
     """
     flavor = 'postgresql'
-    supports_multivalues_insert = True
 
     @classmethod
     def connect(cls):