sqlalchemy: lib/sqlalchemy/dialects/mssql/pymssql.py@230819db717a

- object_session() raises the proper
UnmappedInstanceError when presented with an
unmapped instance. [ticket:1881]

     1 """

     2 Support for the pymssql dialect.

     4 This dialect supports pymssql 1.0 and greater.

     6 pymssql is available at:

     8     http://pymssql.sourceforge.net/

    10 Connecting

    11 ^^^^^^^^^^

    13 Sample connect string::

    15     mssql+pymssql://<username>:<password>@<freetds_name>

    17 Adding "?charset=utf8" or similar will cause pymssql to return

    18 strings as Python unicode objects.   This can potentially improve

    19 performance in some scenarios as decoding of strings is

    20 handled natively.

    22 Limitations

    23 ^^^^^^^^^^^

    25 pymssql inherits a lot of limitations from FreeTDS, including:

    27 * no support for multibyte schema identifiers

    28 * poor support for large decimals

    29 * poor support for binary fields

    30 * poor support for VARCHAR/CHAR fields over 255 characters

    32 Please consult the pymssql documentation for further information.

    34 """

    35 from sqlalchemy.dialects.mssql.base import MSDialect

    36 from sqlalchemy import types as sqltypes, util, processors

    37 import re

    38 import decimal

    40 class _MSNumeric_pymssql(sqltypes.Numeric):

    41     def result_processor(self, dialect, type_):

    42         if not self.asdecimal:

    43             return processors.to_float

    44         else:

    45             return sqltypes.Numeric.result_processor(self, dialect, type_)

    47 class MSDialect_pymssql(MSDialect):

    48     supports_sane_rowcount = False

    49     max_identifier_length = 30

    50     driver = 'pymssql'

    52     colspecs = util.update_copy(

    53         MSDialect.colspecs,

    54         {

    55             sqltypes.Numeric:_MSNumeric_pymssql,

    56             sqltypes.Float:sqltypes.Float,

    57         }

    58     )

    59     @classmethod

    60     def dbapi(cls):

    61         module = __import__('pymssql')

    62         # pymmsql doesn't have a Binary method.  we use string

    63         # TODO: monkeypatching here is less than ideal

    64         module.Binary = str

    66         client_ver = tuple(int(x) for x in module.__version__.split("."))

    67         if client_ver < (1, ):

    68             util.warn("The pymssql dialect expects at least "

    69                             "the 1.0 series of the pymssql DBAPI.")

    70         return module

    72     def __init__(self, **params):

    73         super(MSDialect_pymssql, self).__init__(**params)

    74         self.use_scope_identity = True

    76     def _get_server_version_info(self, connection):

    77         vers = connection.scalar("select @@version")

    78         m = re.match(

    79             r"Microsoft SQL Server.*? - (\d+).(\d+).(\d+).(\d+)", vers)

    80         if m:

    81             return tuple(int(x) for x in m.group(1, 2, 3, 4))

    82         else:

    83             return None

    85     def create_connect_args(self, url):

    86         opts = url.translate_connect_args(username='user')

    87         opts.update(url.query)

    88         opts.pop('port', None)

    89         return [[], opts]

    91     def is_disconnect(self, e):

    92         for msg in (

    93             "Error 10054",

    94             "Not connected to any MS SQL server",

    95             "Connection is closed"

    96         ):

    97             if msg in str(e):

    98                 return True

    99         else:

   100             return False

   102 dialect = MSDialect_pymssql

sqlalchemy / file revision