I'm attempting to read a mdb Access database using mdbtools 0.7 and pyodbc 3.0.7 with the following code:

import pyodbc

MDB = 'database.mdb'

# connect to db
odbc_connection_str = 'DRIVER={MDBTools};DBQ=%s;' % (MDB,)
connection = pyodbc.connect(odbc_connection_str)
cursor = connection.cursor()

SQL = 'SELECT * FROM mytable'
rows = cursor.execute(SQL).fetchall()

for row in rows:
    print row

However, this throws the exception:

Traceback (most recent call last):
  File "test.py", line 26, in <module>
    rows = cursor.execute(SQL).fetchall()
  File "/usr/lib/python2.7/decimal.py", line 548, in __new__
    "Invalid literal for Decimal: %r" % value)
  File "/usr/lib/python2.7/decimal.py", line 3866, in _raise_error
    raise error(explanation)
decimal.InvalidOperation: Invalid literal for Decimal: u''

Presumably, pyodbc is attempting to interpret a null decimal column value, being returned as u'', as a non-null value. A u'' value should be interpreted as the Python None, not throw an exception.