FIX: Removed aggressive datetime parsing (#235)

Author: arvis108

mssql_python/cursor.py

@@ -362,7 +362,7 @@ def _map_sql_type(self, param, parameters_list, i, min_val=None, max_val=None):
                     0,
                     False,
                 )
-            
+                
             try:
                 val = uuid.UUID(param)
                 parameters_list[i] = val.bytes_le
@@ -376,38 +376,6 @@ def _map_sql_type(self, param, parameters_list, i, min_val=None, max_val=None):
             except ValueError:
                 pass
 
-
-            # Attempt to parse as date, datetime, datetime2, timestamp, smalldatetime or time
-            if self._parse_date(param):
-                parameters_list[i] = self._parse_date(
-                    param
-                )  # Replace the parameter with the date object
-                return (
-                    ddbc_sql_const.SQL_DATE.value,
-                    ddbc_sql_const.SQL_C_TYPE_DATE.value,
-                    10,
-                    0,
-                    False,
-                )
-            if self._parse_datetime(param):
-                parameters_list[i] = self._parse_datetime(param)
-                return (
-                    ddbc_sql_const.SQL_TIMESTAMP.value,
-                    ddbc_sql_const.SQL_C_TYPE_TIMESTAMP.value,
-                    26,
-                    6,
-                    False,
-                )
-            if self._parse_time(param):
-                parameters_list[i] = self._parse_time(param)
-                return (
-                    ddbc_sql_const.SQL_TIME.value,
-                    ddbc_sql_const.SQL_C_TYPE_TIME.value,
-                    8,
-                    0,
-                    False,
-                )
-
             # String mapping logic here
             is_unicode = self._is_unicode_string(param)
 

tests/test_004_cursor.py

@@ -10661,6 +10661,89 @@ def test_decimal_separator_calculations(cursor, db_connection):
         # Cleanup
         cursor.execute("DROP TABLE IF EXISTS #pytest_decimal_calc_test")
 
+def test_date_string_parameter_binding(cursor, db_connection):
+    """Verify that date-like strings are treated as strings in parameter binding"""
+    table_name = "#pytest_date_string"
+    try:
+        drop_table_if_exists(cursor, table_name)
+        cursor.execute(f"""
+            CREATE TABLE {table_name} (
+                a_column VARCHAR(20)
+            )
+        """)
+        cursor.execute(f"INSERT INTO {table_name} (a_column) VALUES ('string1'), ('string2')")
+        db_connection.commit()
+
+        date_str = "2025-08-12"
+
+        # Should fail to match anything, since binding may treat it as DATE not VARCHAR
+        cursor.execute(f"SELECT a_column FROM {table_name} WHERE RIGHT(a_column, 10) = ?", (date_str,))
+        rows = cursor.fetchall()
+
+        assert rows == [], f"Expected no match for date-like string, got {rows}"
+
+    except Exception as e:
+        pytest.fail(f"Date string parameter binding test failed: {e}")
+    finally:
+        drop_table_if_exists(cursor, table_name)
+        db_connection.commit()
+
+def test_time_string_parameter_binding(cursor, db_connection):
+    """Verify that time-like strings are treated as strings in parameter binding"""
+    table_name = "#pytest_time_string"
+    try:
+        drop_table_if_exists(cursor, table_name)
+        cursor.execute(f"""
+            CREATE TABLE {table_name} (
+                time_col VARCHAR(22)
+            )
+        """)
+        cursor.execute(f"INSERT INTO {table_name} (time_col) VALUES ('prefix_14:30:45_suffix')")
+        db_connection.commit()
+
+        time_str = "14:30:45"
+
+        # This should fail because '14:30:45' gets converted to TIME type
+        # and SQL Server can't compare TIME against VARCHAR with prefix/suffix
+        cursor.execute(f"SELECT time_col FROM {table_name} WHERE time_col = ?", (time_str,))
+        rows = cursor.fetchall()
+
+        assert rows == [], f"Expected no match for time-like string, got {rows}"
+
+    except Exception as e:
+        pytest.fail(f"Time string parameter binding test failed: {e}")
+    finally:
+        drop_table_if_exists(cursor, table_name)
+        db_connection.commit()
+
+def test_datetime_string_parameter_binding(cursor, db_connection):
+    """Verify that datetime-like strings are treated as strings in parameter binding"""
+    table_name = "#pytest_datetime_string"
+    try:
+        drop_table_if_exists(cursor, table_name)
+        cursor.execute(f"""
+            CREATE TABLE {table_name} (
+                datetime_col VARCHAR(33)
+            )
+        """)
+        cursor.execute(f"INSERT INTO {table_name} (datetime_col) VALUES ('prefix_2025-08-12T14:30:45_suffix')")
+        db_connection.commit()
+
+        datetime_str = "2025-08-12T14:30:45"
+
+        # This should fail because '2025-08-12T14:30:45' gets converted to TIMESTAMP type
+        # and SQL Server can't compare TIMESTAMP against VARCHAR with prefix/suffix
+        cursor.execute(f"SELECT datetime_col FROM {table_name} WHERE datetime_col = ?", (datetime_str,))
+        rows = cursor.fetchall()
+
+        assert rows == [], f"Expected no match for datetime-like string, got {rows}"
+
+    except Exception as e:
+        pytest.fail(f"Datetime string parameter binding test failed: {e}")
+    finally:
+        drop_table_if_exists(cursor, table_name)
+        db_connection.commit()
+        
 def test_close(db_connection):
     """Test closing the cursor"""
     try: