fix(cursor, write_dataframe): respect paramstyle

Author: Brooke-white

redshift_connector/cursor.py

@@ -555,7 +555,7 @@ def __is_valid_table(self: "Cursor", table: str) -> bool:
 
     def write_dataframe(self: "Cursor", df: "pandas.DataFrame", table: str) -> None:
         """
-        Inserts a :class:`pandas.DataFrame` into an table within the current database.
+        Inserts a :class:`pandas.DataFrame` into a table within the current database.
 
         Parameters
         ----------
@@ -579,10 +579,21 @@ def write_dataframe(self: "Cursor", df: "pandas.DataFrame", table: str) -> None:
         sql: str = "insert into {table} values ({placeholder})".format(
             table=sanitized_table_name, placeholder=placeholder
         )
-        if len(arrays) == 1:
-            self.execute(sql, arrays[0])
-        elif len(arrays) > 1:
-            self.executemany(sql, arrays)
+        cursor_paramstyle: str = self.paramstyle
+        try:
+            # force using FORMAT i.e. %s paramstyle for the current statement, then revert the
+            # cursor to use the cursor's original paramstyle
+            self.paramstyle = DbApiParamstyle.FORMAT.value
+            if len(arrays) == 1:
+                self.execute(sql, arrays[0])
+            elif len(arrays) > 1:
+                self.executemany(sql, arrays)
+        except:
+            raise InterfaceError(
+                "An error occurred when attempting to insert the pandas.DataFrame into ${}".format(table)
+            )
+        finally:
+            self.paramstyle = cursor_paramstyle
 
     def fetch_numpy_array(self: "Cursor", num: typing.Optional[int] = None) -> "numpy.ndarray":
         """

test/integration/test_pandas.py

@@ -4,6 +4,7 @@
 import pytest  # type: ignore
 
 import redshift_connector
+from redshift_connector.config import DbApiParamstyle
 
 # Tests relating to the pandas and numpy operation of the database driver
 # redshift_connector custom interface.
@@ -58,7 +59,8 @@ def test_fetch_dataframe(db_table):
 
 
 @pandas_only
-def test_write_dataframe(db_table):
+@pytest.mark.parametrize("paramstyle", DbApiParamstyle.list())
+def test_write_dataframe(db_table, paramstyle):
     import numpy as np
     import pandas as pd
 
@@ -71,12 +73,16 @@ def test_write_dataframe(db_table):
         ),
         columns=["bookname", "author‎"],
     )
+    db_table.paramstyle = paramstyle
+
     with db_table.cursor() as cursor:
         cursor.write_dataframe(df, "book")
         cursor.execute("select * from book; ")
         result = cursor.fetchall()
         assert len(np.array(result)) == 2
 
+    assert db_table.paramstyle == paramstyle
+
 
 @numpy_only
 def test_fetch_numpyarray(db_table):