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Updated SqlAlchemy + the new files

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This commit is contained in:
Christoffer Viken
2017-04-15 16:33:29 +00:00
parent e3267d4bda
commit 4669737fe3
134 changed files with 66374 additions and 4528 deletions
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sqlalchemy/dialects/mssql/pyodbc.py
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@@ -1,99 +1,135 @@
"""
Support for MS-SQL via pyodbc.
# mssql/pyodbc.py
# Copyright (C) 2005-2017 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
pyodbc is available at:
r"""
.. dialect:: mssql+pyodbc
:name: PyODBC
:dbapi: pyodbc
:connectstring: mssql+pyodbc://<username>:<password>@<dsnname>
:url: http://pypi.python.org/pypi/pyodbc/
http://pypi.python.org/pypi/pyodbc/
Connecting to PyODBC
--------------------
Connecting
^^^^^^^^^^
The URL here is to be translated to PyODBC connection strings, as
detailed in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_.
Examples of pyodbc connection string URLs:
DSN Connections
^^^^^^^^^^^^^^^
* ``mssql+pyodbc://mydsn`` - connects using the specified DSN named ``mydsn``.
The connection string that is created will appear like::
A DSN-based connection is **preferred** overall when using ODBC. A
basic DSN-based connection looks like::
dsn=mydsn;Trusted_Connection=Yes
engine = create_engine("mssql+pyodbc://scott:tiger@some_dsn")
* ``mssql+pyodbc://user:pass@mydsn`` - connects using the DSN named
``mydsn`` passing in the ``UID`` and ``PWD`` information. The
connection string that is created will appear like::
Which above, will pass the following connection string to PyODBC::
dsn=mydsn;UID=user;PWD=pass
* ``mssql+pyodbc://user:pass@mydsn/?LANGUAGE=us_english`` - connects
using the DSN named ``mydsn`` passing in the ``UID`` and ``PWD``
information, plus the additional connection configuration option
``LANGUAGE``. The connection string that is created will appear
like::
If the username and password are omitted, the DSN form will also add
the ``Trusted_Connection=yes`` directive to the ODBC string.
dsn=mydsn;UID=user;PWD=pass;LANGUAGE=us_english
Hostname Connections
^^^^^^^^^^^^^^^^^^^^
* ``mssql+pyodbc://user:pass@host/db`` - connects using a connection string
dynamically created that would appear like::
Hostname-based connections are **not preferred**, however are supported.
The ODBC driver name must be explicitly specified::
DRIVER={SQL Server};Server=host;Database=db;UID=user;PWD=pass
engine = create_engine("mssql+pyodbc://scott:tiger@myhost:port/databasename?driver=SQL+Server+Native+Client+10.0")
* ``mssql+pyodbc://user:pass@host:123/db`` - connects using a connection
string that is dynamically created, which also includes the port
information using the comma syntax. If your connection string
requires the port information to be passed as a ``port`` keyword
see the next example. This will create the following connection
string::
.. versionchanged:: 1.0.0 Hostname-based PyODBC connections now require the
SQL Server driver name specified explicitly. SQLAlchemy cannot
choose an optimal default here as it varies based on platform
and installed drivers.
DRIVER={SQL Server};Server=host,123;Database=db;UID=user;PWD=pass
Other keywords interpreted by the Pyodbc dialect to be passed to
``pyodbc.connect()`` in both the DSN and hostname cases include:
``odbc_autotranslate``, ``ansi``, ``unicode_results``, ``autocommit``.
* ``mssql+pyodbc://user:pass@host/db?port=123`` - connects using a connection
string that is dynamically created that includes the port
information as a separate ``port`` keyword. This will create the
following connection string::
Pass through exact Pyodbc string
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
DRIVER={SQL Server};Server=host;Database=db;UID=user;PWD=pass;port=123
A PyODBC connection string can also be sent exactly as specified in
`ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_
into the driver using the parameter ``odbc_connect``. The delimeters must be URL escaped, however,
as illustrated below using ``urllib.quote_plus``::
If you require a connection string that is outside the options
presented above, use the ``odbc_connect`` keyword to pass in a
urlencoded connection string. What gets passed in will be urldecoded
and passed directly.
import urllib
params = urllib.quote_plus("DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password")
For example::
engine = create_engine("mssql+pyodbc:///?odbc_connect=%s" % params)
mssql+pyodbc:///?odbc_connect=dsn%3Dmydsn%3BDatabase%3Ddb
would create the following connection string::
Unicode Binds
-------------
dsn=mydsn;Database=db
The current state of PyODBC on a unix backend with FreeTDS and/or
EasySoft is poor regarding unicode; different OS platforms and versions of
UnixODBC versus IODBC versus FreeTDS/EasySoft versus PyODBC itself
dramatically alter how strings are received. The PyODBC dialect attempts to
use all the information it knows to determine whether or not a Python unicode
literal can be passed directly to the PyODBC driver or not; while SQLAlchemy
can encode these to bytestrings first, some users have reported that PyODBC
mis-handles bytestrings for certain encodings and requires a Python unicode
object, while the author has observed widespread cases where a Python unicode
is completely misinterpreted by PyODBC, particularly when dealing with
the information schema tables used in table reflection, and the value
must first be encoded to a bytestring.
Encoding your connection string can be easily accomplished through
the python shell. For example::
It is for this reason that whether or not unicode literals for bound
parameters be sent to PyODBC can be controlled using the
``supports_unicode_binds`` parameter to ``create_engine()``. When
left at its default of ``None``, the PyODBC dialect will use its
best guess as to whether or not the driver deals with unicode literals
well. When ``False``, unicode literals will be encoded first, and when
``True`` unicode literals will be passed straight through. This is an interim
flag that hopefully should not be needed when the unicode situation stabilizes
for unix + PyODBC.
>>> import urllib
>>> urllib.quote_plus('dsn=mydsn;Database=db')
'dsn%3Dmydsn%3BDatabase%3Ddb'
.. versionadded:: 0.7.7
``supports_unicode_binds`` parameter to ``create_engine()``\ .
Rowcount Support
----------------
Pyodbc only has partial support for rowcount. See the notes at
:ref:`mssql_rowcount_versioning` for important notes when using ORM
versioning.
"""
from sqlalchemy.dialects.mssql.base import MSExecutionContext, MSDialect
from sqlalchemy.connectors.pyodbc import PyODBCConnector
from sqlalchemy import types as sqltypes, util
from .base import MSExecutionContext, MSDialect, VARBINARY
from ...connectors.pyodbc import PyODBCConnector
from ... import types as sqltypes, util, exc
import decimal
import re
class _ms_numeric_pyodbc(object):
class _MSNumeric_pyodbc(sqltypes.Numeric):
"""Turns Decimals with adjusted() < 0 or > 7 into strings.
This is the only method that is proven to work with Pyodbc+MSSQL
without crashing (floats can be used but seem to cause sporadic
crashes).
The routines here are needed for older pyodbc versions
as well as current mxODBC versions.
"""
def bind_processor(self, dialect):
super_process = super(_MSNumeric_pyodbc, self).bind_processor(dialect)
super_process = super(_ms_numeric_pyodbc, self).\
bind_processor(dialect)
if not dialect._need_decimal_fix:
return super_process
def process(value):
if self.asdecimal and \
isinstance(value, decimal.Decimal):
adjusted = value.adjusted()
if adjusted < 0:
return self._small_dec_to_string(value)
@@ -105,72 +141,106 @@ class _MSNumeric_pyodbc(sqltypes.Numeric):
else:
return value
return process
# these routines needed for older versions of pyodbc.
# as of 2.1.8 this logic is integrated.
def _small_dec_to_string(self, value):
return "%s0.%s%s" % (
(value < 0 and '-' or ''),
'0' * (abs(value.adjusted()) - 1),
"".join([str(nint) for nint in value._int]))
(value < 0 and '-' or ''),
'0' * (abs(value.adjusted()) - 1),
"".join([str(nint) for nint in value.as_tuple()[1]]))
def _large_dec_to_string(self, value):
_int = value.as_tuple()[1]
if 'E' in str(value):
result = "%s%s%s" % (
(value < 0 and '-' or ''),
"".join([str(s) for s in value._int]),
"0" * (value.adjusted() - (len(value._int)-1)))
(value < 0 and '-' or ''),
"".join([str(s) for s in _int]),
"0" * (value.adjusted() - (len(_int) - 1)))
else:
if (len(value._int) - 1) > value.adjusted():
if (len(_int) - 1) > value.adjusted():
result = "%s%s.%s" % (
(value < 0 and '-' or ''),
"".join([str(s) for s in value._int][0:value.adjusted() + 1]),
"".join([str(s) for s in value._int][value.adjusted() + 1:]))
(value < 0 and '-' or ''),
"".join(
[str(s) for s in _int][0:value.adjusted() + 1]),
"".join(
[str(s) for s in _int][value.adjusted() + 1:]))
else:
result = "%s%s" % (
(value < 0 and '-' or ''),
"".join([str(s) for s in value._int][0:value.adjusted() + 1]))
(value < 0 and '-' or ''),
"".join(
[str(s) for s in _int][0:value.adjusted() + 1]))
return result
class _MSNumeric_pyodbc(_ms_numeric_pyodbc, sqltypes.Numeric):
pass
class _MSFloat_pyodbc(_ms_numeric_pyodbc, sqltypes.Float):
pass
class _VARBINARY_pyodbc(VARBINARY):
def bind_processor(self, dialect):
if dialect.dbapi is None:
return None
DBAPIBinary = dialect.dbapi.Binary
def process(value):
if value is not None:
return DBAPIBinary(value)
else:
# pyodbc-specific
return dialect.dbapi.BinaryNull
return process
class MSExecutionContext_pyodbc(MSExecutionContext):
_embedded_scope_identity = False
def pre_exec(self):
"""where appropriate, issue "select scope_identity()" in the same statement.
"""where appropriate, issue "select scope_identity()" in the same
statement.
Background on why "scope_identity()" is preferable to "@@identity":
http://msdn.microsoft.com/en-us/library/ms190315.aspx
Background on why we attempt to embed "scope_identity()" into the same
statement as the INSERT:
http://code.google.com/p/pyodbc/wiki/FAQs#How_do_I_retrieve_autogenerated/identity_values?
"""
super(MSExecutionContext_pyodbc, self).pre_exec()
# don't embed the scope_identity select into an "INSERT .. DEFAULT VALUES"
# don't embed the scope_identity select into an
# "INSERT .. DEFAULT VALUES"
if self._select_lastrowid and \
self.dialect.use_scope_identity and \
len(self.parameters[0]):
self._embedded_scope_identity = True
self.statement += "; select scope_identity()"
def post_exec(self):
if self._embedded_scope_identity:
# Fetch the last inserted id from the manipulated statement
# We may have to skip over a number of result sets with no data (due to triggers, etc.)
# We may have to skip over a number of result sets with
# no data (due to triggers, etc.)
while True:
try:
# fetchall() ensures the cursor is consumed
# fetchall() ensures the cursor is consumed
# without closing it (FreeTDS particularly)
row = self.cursor.fetchall()[0]
row = self.cursor.fetchall()[0]
break
except self.dialect.dbapi.Error, e:
except self.dialect.dbapi.Error as e:
# no way around this - nextset() consumes the previous set
# so we need to just keep flipping
self.cursor.nextset()
self._lastrowid = int(row[0])
else:
super(MSExecutionContext_pyodbc, self).post_exec()
@@ -180,18 +250,43 @@ class MSDialect_pyodbc(PyODBCConnector, MSDialect):
execution_ctx_cls = MSExecutionContext_pyodbc
pyodbc_driver_name = 'SQL Server'
colspecs = util.update_copy(
MSDialect.colspecs,
{
sqltypes.Numeric:_MSNumeric_pyodbc
sqltypes.Numeric: _MSNumeric_pyodbc,
sqltypes.Float: _MSFloat_pyodbc,
VARBINARY: _VARBINARY_pyodbc,
sqltypes.LargeBinary: _VARBINARY_pyodbc,
}
)
def __init__(self, description_encoding='latin-1', **params):
def __init__(self, description_encoding=None, **params):
if 'description_encoding' in params:
self.description_encoding = params.pop('description_encoding')
super(MSDialect_pyodbc, self).__init__(**params)
self.description_encoding = description_encoding
self.use_scope_identity = self.dbapi and hasattr(self.dbapi.Cursor, 'nextset')
self.use_scope_identity = self.use_scope_identity and \
self.dbapi and \
hasattr(self.dbapi.Cursor, 'nextset')
self._need_decimal_fix = self.dbapi and \
self._dbapi_version() < (2, 1, 8)
def _get_server_version_info(self, connection):
try:
raw = connection.scalar("SELECT SERVERPROPERTY('ProductVersion')")
except exc.DBAPIError:
# SQL Server docs indicate this function isn't present prior to
# 2008; additionally, unknown combinations of pyodbc aren't
# able to run this query.
return super(MSDialect_pyodbc, self).\
_get_server_version_info(connection)
else:
version = []
r = re.compile(r'[.\-]')
for n in r.split(raw):
try:
version.append(int(n))
except ValueError:
version.append(n)
return tuple(version)
dialect = MSDialect_pyodbc