Merge pull request #346 from baldwicc/datetimeoffset-patch

fix: adds pyodbc output converter for DATETIMEOFFSET data types

Author: sdebruyn

dbt/adapters/sqlserver/sql_server_connection_manager.py

@@ -1,3 +1,4 @@
+import datetime as dt
 import struct
 import time
 from contextlib import contextmanager
@@ -233,6 +234,40 @@ def bool_to_connection_string_arg(key: str, value: bool) -> str:
     return f'{key}={"Yes" if value else "No"}'
 
 
+def byte_array_to_datetime(value: bytes) -> dt.datetime:
+    """
+    Converts a DATETIMEOFFSET byte array to a timezone-aware datetime object
+
+    Parameters
+    ----------
+    value : buffer
+        A binary value conforming to SQL_SS_TIMESTAMPOFFSET_STRUCT
+
+    Returns
+    -------
+    out : datetime
+
+    Source
+    ------
+    SQL_SS_TIMESTAMPOFFSET datatype and SQL_SS_TIMESTAMPOFFSET_STRUCT layout:
+    https://learn.microsoft.com/sql/relational-databases/native-client-odbc-date-time/data-type-support-for-odbc-date-and-time-improvements
+    """
+    # unpack 20 bytes of data into a tuple of 9 values
+    tup = struct.unpack("<6hI2h", value)
+
+    # construct a datetime object
+    return dt.datetime(
+        year=tup[0],
+        month=tup[1],
+        day=tup[2],
+        hour=tup[3],
+        minute=tup[4],
+        second=tup[5],
+        microsecond=tup[6] // 1000,  # https://bugs.python.org/issue15443
+        tzinfo=dt.timezone(dt.timedelta(hours=tup[7], minutes=tup[8])),
+    )
+
+
 class SQLServerConnectionManager(SQLConnectionManager):
     TYPE = "sqlserver"
 
@@ -394,6 +429,10 @@ def add_query(
             else:
                 cursor.execute(sql, bindings)
 
+            # convert DATETIMEOFFSET binary structures to datetime ojbects
+            # https://github.com/mkleehammer/pyodbc/issues/134#issuecomment-281739794
+            connection.handle.add_output_converter(-155, byte_array_to_datetime)
+
             logger.debug(
                 "SQL status: {} in {:0.2f} seconds".format(
                     self.get_response(cursor), (time.time() - pre)

tests/unit/adapters/sqlserver/test_sql_server_connection_manager.py

@@ -7,6 +7,7 @@
 
 from dbt.adapters.sqlserver.sql_server_connection_manager import (
     bool_to_connection_string_arg,
+    byte_array_to_datetime,
     get_pyodbc_attrs_before,
 )
 from dbt.adapters.sqlserver.sql_server_credentials import SQLServerCredentials
@@ -76,3 +77,56 @@ def test_get_pyodbc_attrs_before_contains_access_token_key_for_cli_authenticatio
 )
 def test_bool_to_connection_string_arg(key: str, value: bool, expected: str) -> None:
     assert bool_to_connection_string_arg(key, value) == expected
+
+
+@pytest.mark.parametrize(
+    "value, expected_datetime, expected_str",
+    [
+        (
+            bytes(
+                [
+                    0xE6,
+                    0x07,  # 2022       year            unsigned short
+                    0x0C,
+                    0x00,  # 12         month           unsigned short
+                    0x11,
+                    0x00,  # 17         day             unsigned short
+                    0x11,
+                    0x00,  # 17         hour            unsigned short
+                    0x34,
+                    0x00,  # 52         minute          unsigned short
+                    0x12,
+                    0x00,  # 18         second          unsigned short
+                    0xBC,
+                    0xCC,
+                    0x5B,
+                    0x07,  # 123456700  10⁻⁷ second     unsigned long
+                    0xFE,
+                    0xFF,  # -2          offset hour     signed short
+                    0xE2,
+                    0xFF,  # -30         offset minute   signed short
+                ]
+            ),
+            dt.datetime(
+                year=2022,
+                month=12,
+                day=17,
+                hour=17,
+                minute=52,
+                second=18,
+                microsecond=123456700 // 1000,  # 10⁻⁶ second
+                tzinfo=dt.timezone(dt.timedelta(hours=-2, minutes=-30)),
+            ),
+            "2022-12-17 17:52:18.123456-02:30",
+        )
+    ],
+)
+def test_byte_array_to_datetime(
+    value: bytes, expected_datetime: dt.datetime, expected_str: str
+) -> None:
+    """
+    Assert SQL_SS_TIMESTAMPOFFSET_STRUCT bytes are converted to datetime and str
+    https://learn.microsoft.com/sql/relational-databases/native-client-odbc-date-time/data-type-support-for-odbc-date-and-time-improvements#sql_ss_timestampoffset_struct
+    """
+    assert byte_array_to_datetime(value) == expected_datetime
+    assert str(byte_array_to_datetime(value)) == expected_str