tldr: refactoring

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/__init__.py

@@ -0,0 +1,85 @@
+# mssql/__init__.py
+# Copyright (C) 2005-2019 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
+
+from . import adodbapi  # noqa
+from . import base  # noqa
+from . import mxodbc  # noqa
+from . import pymssql  # noqa
+from . import pyodbc  # noqa
+from . import zxjdbc  # noqa
+from .base import BIGINT
+from .base import BINARY
+from .base import BIT
+from .base import CHAR
+from .base import DATE
+from .base import DATETIME
+from .base import DATETIME2
+from .base import DATETIMEOFFSET
+from .base import DECIMAL
+from .base import FLOAT
+from .base import IMAGE
+from .base import INTEGER
+from .base import MONEY
+from .base import NCHAR
+from .base import NTEXT
+from .base import NUMERIC
+from .base import NVARCHAR
+from .base import REAL
+from .base import ROWVERSION
+from .base import SMALLDATETIME
+from .base import SMALLINT
+from .base import SMALLMONEY
+from .base import SQL_VARIANT
+from .base import TEXT
+from .base import TIME
+from .base import TIMESTAMP
+from .base import TINYINT
+from .base import try_cast
+from .base import UNIQUEIDENTIFIER
+from .base import VARBINARY
+from .base import VARCHAR
+from .base import XML
+
+
+base.dialect = dialect = pyodbc.dialect
+
+
+__all__ = (
+    "INTEGER",
+    "BIGINT",
+    "SMALLINT",
+    "TINYINT",
+    "VARCHAR",
+    "NVARCHAR",
+    "CHAR",
+    "NCHAR",
+    "TEXT",
+    "NTEXT",
+    "DECIMAL",
+    "NUMERIC",
+    "FLOAT",
+    "DATETIME",
+    "DATETIME2",
+    "DATETIMEOFFSET",
+    "DATE",
+    "TIME",
+    "SMALLDATETIME",
+    "BINARY",
+    "VARBINARY",
+    "BIT",
+    "REAL",
+    "IMAGE",
+    "TIMESTAMP",
+    "ROWVERSION",
+    "MONEY",
+    "SMALLMONEY",
+    "UNIQUEIDENTIFIER",
+    "SQL_VARIANT",
+    "XML",
+    "dialect",
+    "try_cast",
+)

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/adodbapi.py

@@ -0,0 +1,90 @@
+# mssql/adodbapi.py
+# Copyright (C) 2005-2019 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
+
+"""
+.. dialect:: mssql+adodbapi
+    :name: adodbapi
+    :dbapi: adodbapi
+    :connectstring: mssql+adodbapi://<username>:<password>@<dsnname>
+    :url: http://adodbapi.sourceforge.net/
+
+.. note::
+
+    The adodbapi dialect is not implemented in SQLAlchemy versions 0.6 and
+    above at this time.
+
+"""
+import datetime
+import sys
+
+from sqlalchemy import types as sqltypes
+from sqlalchemy import util
+from sqlalchemy.dialects.mssql.base import MSDateTime
+from sqlalchemy.dialects.mssql.base import MSDialect
+
+
+class MSDateTime_adodbapi(MSDateTime):
+    def result_processor(self, dialect, coltype):
+        def process(value):
+            # adodbapi will return datetimes with empty time
+            # values as datetime.date() objects.
+            # Promote them back to full datetime.datetime()
+            if type(value) is datetime.date:
+                return datetime.datetime(value.year, value.month, value.day)
+            return value
+
+        return process
+
+
+class MSDialect_adodbapi(MSDialect):
+    supports_sane_rowcount = True
+    supports_sane_multi_rowcount = True
+    supports_unicode = sys.maxunicode == 65535
+    supports_unicode_statements = True
+    driver = "adodbapi"
+
+    @classmethod
+    def import_dbapi(cls):
+        import adodbapi as module
+
+        return module
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs, {sqltypes.DateTime: MSDateTime_adodbapi}
+    )
+
+    def create_connect_args(self, url):
+        def check_quote(token):
+            if ";" in str(token):
+                token = "'%s'" % token
+            return token
+
+        keys = dict((k, check_quote(v)) for k, v in url.query.items())
+
+        connectors = ["Provider=SQLOLEDB"]
+        if "port" in keys:
+            connectors.append(
+                "Data Source=%s, %s" % (keys.get("host"), keys.get("port"))
+            )
+        else:
+            connectors.append("Data Source=%s" % keys.get("host"))
+        connectors.append("Initial Catalog=%s" % keys.get("database"))
+        user = keys.get("user")
+        if user:
+            connectors.append("User Id=%s" % user)
+            connectors.append("Password=%s" % keys.get("password", ""))
+        else:
+            connectors.append("Integrated Security=SSPI")
+        return [[";".join(connectors)], {}]
+
+    def is_disconnect(self, e, connection, cursor):
+        return isinstance(
+            e, self.dbapi.adodbapi.DatabaseError
+        ) and "'connection failure'" in str(e)
+
+
+dialect = MSDialect_adodbapi

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/information_schema.py

@@ -0,0 +1,163 @@
+# mssql/information_schema.py
+# Copyright (C) 2005-2019 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
+
+# TODO: should be using the sys. catalog with SQL Server, not information
+# schema
+
+from ... import cast
+from ... import Column
+from ... import MetaData
+from ... import Table
+from ... import util
+from ...ext.compiler import compiles
+from ...sql import expression
+from ...types import Integer
+from ...types import String
+from ...types import TypeDecorator
+from ...types import Unicode
+
+
+ischema = MetaData()
+
+
+class CoerceUnicode(TypeDecorator):
+    impl = Unicode
+
+    def process_bind_param(self, value, dialect):
+        if util.py2k and isinstance(value, util.binary_type):
+            value = value.decode(dialect.encoding)
+        return value
+
+    def bind_expression(self, bindvalue):
+        return _cast_on_2005(bindvalue)
+
+
+class _cast_on_2005(expression.ColumnElement):
+    def __init__(self, bindvalue):
+        self.bindvalue = bindvalue
+
+
+@compiles(_cast_on_2005)
+def _compile(element, compiler, **kw):
+    from . import base
+
+    if (
+        compiler.dialect.server_version_info is None
+        or compiler.dialect.server_version_info < base.MS_2005_VERSION
+    ):
+        return compiler.process(element.bindvalue, **kw)
+    else:
+        return compiler.process(cast(element.bindvalue, Unicode), **kw)
+
+
+schemata = Table(
+    "SCHEMATA",
+    ischema,
+    Column("CATALOG_NAME", CoerceUnicode, key="catalog_name"),
+    Column("SCHEMA_NAME", CoerceUnicode, key="schema_name"),
+    Column("SCHEMA_OWNER", CoerceUnicode, key="schema_owner"),
+    schema="INFORMATION_SCHEMA",
+)
+
+tables = Table(
+    "TABLES",
+    ischema,
+    Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"),
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("TABLE_TYPE", CoerceUnicode, key="table_type"),
+    schema="INFORMATION_SCHEMA",
+)
+
+columns = Table(
+    "COLUMNS",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("IS_NULLABLE", Integer, key="is_nullable"),
+    Column("DATA_TYPE", String, key="data_type"),
+    Column("ORDINAL_POSITION", Integer, key="ordinal_position"),
+    Column(
+        "CHARACTER_MAXIMUM_LENGTH", Integer, key="character_maximum_length"
+    ),
+    Column("NUMERIC_PRECISION", Integer, key="numeric_precision"),
+    Column("NUMERIC_SCALE", Integer, key="numeric_scale"),
+    Column("COLUMN_DEFAULT", Integer, key="column_default"),
+    Column("COLLATION_NAME", String, key="collation_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+constraints = Table(
+    "TABLE_CONSTRAINTS",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    Column("CONSTRAINT_TYPE", CoerceUnicode, key="constraint_type"),
+    schema="INFORMATION_SCHEMA",
+)
+
+column_constraints = Table(
+    "CONSTRAINT_COLUMN_USAGE",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+key_constraints = Table(
+    "KEY_COLUMN_USAGE",
+    ischema,
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("COLUMN_NAME", CoerceUnicode, key="column_name"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"),
+    Column("ORDINAL_POSITION", Integer, key="ordinal_position"),
+    schema="INFORMATION_SCHEMA",
+)
+
+ref_constraints = Table(
+    "REFERENTIAL_CONSTRAINTS",
+    ischema,
+    Column("CONSTRAINT_CATALOG", CoerceUnicode, key="constraint_catalog"),
+    Column("CONSTRAINT_SCHEMA", CoerceUnicode, key="constraint_schema"),
+    Column("CONSTRAINT_NAME", CoerceUnicode, key="constraint_name"),
+    # TODO: is CATLOG misspelled ?
+    Column(
+        "UNIQUE_CONSTRAINT_CATLOG",
+        CoerceUnicode,
+        key="unique_constraint_catalog",
+    ),
+    Column(
+        "UNIQUE_CONSTRAINT_SCHEMA",
+        CoerceUnicode,
+        key="unique_constraint_schema",
+    ),
+    Column(
+        "UNIQUE_CONSTRAINT_NAME", CoerceUnicode, key="unique_constraint_name"
+    ),
+    Column("MATCH_OPTION", String, key="match_option"),
+    Column("UPDATE_RULE", String, key="update_rule"),
+    Column("DELETE_RULE", String, key="delete_rule"),
+    schema="INFORMATION_SCHEMA",
+)
+
+views = Table(
+    "VIEWS",
+    ischema,
+    Column("TABLE_CATALOG", CoerceUnicode, key="table_catalog"),
+    Column("TABLE_SCHEMA", CoerceUnicode, key="table_schema"),
+    Column("TABLE_NAME", CoerceUnicode, key="table_name"),
+    Column("VIEW_DEFINITION", CoerceUnicode, key="view_definition"),
+    Column("CHECK_OPTION", String, key="check_option"),
+    Column("IS_UPDATABLE", String, key="is_updatable"),
+    schema="INFORMATION_SCHEMA",
+)

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/mxodbc.py

@@ -0,0 +1,146 @@
+# mssql/mxodbc.py
+# Copyright (C) 2005-2019 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
+
+"""
+.. dialect:: mssql+mxodbc
+    :name: mxODBC
+    :dbapi: mxodbc
+    :connectstring: mssql+mxodbc://<username>:<password>@<dsnname>
+    :url: http://www.egenix.com/
+
+Execution Modes
+---------------
+
+mxODBC features two styles of statement execution, using the
+``cursor.execute()`` and ``cursor.executedirect()`` methods (the second being
+an extension to the DBAPI specification). The former makes use of a particular
+API call specific to the SQL Server Native Client ODBC driver known
+SQLDescribeParam, while the latter does not.
+
+mxODBC apparently only makes repeated use of a single prepared statement
+when SQLDescribeParam is used. The advantage to prepared statement reuse is
+one of performance. The disadvantage is that SQLDescribeParam has a limited
+set of scenarios in which bind parameters are understood, including that they
+cannot be placed within the argument lists of function calls, anywhere outside
+the FROM, or even within subqueries within the FROM clause - making the usage
+of bind parameters within SELECT statements impossible for all but the most
+simplistic statements.
+
+For this reason, the mxODBC dialect uses the "native" mode by default only for
+INSERT, UPDATE, and DELETE statements, and uses the escaped string mode for
+all other statements.
+
+This behavior can be controlled via
+:meth:`~sqlalchemy.sql.expression.Executable.execution_options` using the
+``native_odbc_execute`` flag with a value of ``True`` or ``False``, where a
+value of ``True`` will unconditionally use native bind parameters and a value
+of ``False`` will unconditionally use string-escaped parameters.
+
+"""
+
+
+from .base import _MSDate
+from .base import _MSDateTime
+from .base import _MSTime
+from .base import MSDialect
+from .base import VARBINARY
+from .pyodbc import _MSNumeric_pyodbc
+from .pyodbc import MSExecutionContext_pyodbc
+from ... import types as sqltypes
+from ...connectors.mxodbc import MxODBCConnector
+
+
+class _MSNumeric_mxodbc(_MSNumeric_pyodbc):
+    """Include pyodbc's numeric processor.
+    """
+
+
+class _MSDate_mxodbc(_MSDate):
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is not None:
+                return "%s-%s-%s" % (value.year, value.month, value.day)
+            else:
+                return None
+
+        return process
+
+
+class _MSTime_mxodbc(_MSTime):
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is not None:
+                return "%s:%s:%s" % (value.hour, value.minute, value.second)
+            else:
+                return None
+
+        return process
+
+
+class _VARBINARY_mxodbc(VARBINARY):
+
+    """
+    mxODBC Support for VARBINARY column types.
+
+    This handles the special case for null VARBINARY values,
+    which maps None values to the mx.ODBC.Manager.BinaryNull symbol.
+    """
+
+    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:
+                # should pull from mx.ODBC.Manager.BinaryNull
+                return dialect.dbapi.BinaryNull
+
+        return process
+
+
+class MSExecutionContext_mxodbc(MSExecutionContext_pyodbc):
+    """
+    The pyodbc execution context is useful for enabling
+    SELECT SCOPE_IDENTITY in cases where OUTPUT clause
+    does not work (tables with insert triggers).
+    """
+
+    # todo - investigate whether the pyodbc execution context
+    #       is really only being used in cases where OUTPUT
+    #       won't work.
+
+
+class MSDialect_mxodbc(MxODBCConnector, MSDialect):
+
+    # this is only needed if "native ODBC" mode is used,
+    # which is now disabled by default.
+    # statement_compiler = MSSQLStrictCompiler
+
+    execution_ctx_cls = MSExecutionContext_mxodbc
+
+    # flag used by _MSNumeric_mxodbc
+    _need_decimal_fix = True
+
+    colspecs = {
+        sqltypes.Numeric: _MSNumeric_mxodbc,
+        sqltypes.DateTime: _MSDateTime,
+        sqltypes.Date: _MSDate_mxodbc,
+        sqltypes.Time: _MSTime_mxodbc,
+        VARBINARY: _VARBINARY_mxodbc,
+        sqltypes.LargeBinary: _VARBINARY_mxodbc,
+    }
+
+    def __init__(self, description_encoding=None, **params):
+        super(MSDialect_mxodbc, self).__init__(**params)
+        self.description_encoding = description_encoding
+
+
+dialect = MSDialect_mxodbc

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/pymssql.py

@@ -0,0 +1,118 @@
+# mssql/pymssql.py
+# Copyright (C) 2005-2019 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
+
+"""
+.. dialect:: mssql+pymssql
+    :name: pymssql
+    :dbapi: pymssql
+    :connectstring: mssql+pymssql://<username>:<password>@<freetds_name>/?charset=utf8
+    :url: http://pymssql.org/
+
+pymssql is a Python module that provides a Python DBAPI interface around
+`FreeTDS <http://www.freetds.org/>`_.  Compatible builds are available for
+Linux, MacOSX and Windows platforms.
+
+Modern versions of this driver work very well with SQL Server and
+FreeTDS from Linux and is highly recommended.
+
+"""  # noqa
+import re
+
+from .base import MSDialect
+from .base import MSIdentifierPreparer
+from ... import processors
+from ... import types as sqltypes
+from ... import util
+
+
+class _MSNumeric_pymssql(sqltypes.Numeric):
+    def result_processor(self, dialect, type_):
+        if not self.asdecimal:
+            return processors.to_float
+        else:
+            return sqltypes.Numeric.result_processor(self, dialect, type_)
+
+
+class MSIdentifierPreparer_pymssql(MSIdentifierPreparer):
+    def __init__(self, dialect):
+        super(MSIdentifierPreparer_pymssql, self).__init__(dialect)
+        # pymssql has the very unusual behavior that it uses pyformat
+        # yet does not require that percent signs be doubled
+        self._double_percents = False
+
+
+class MSDialect_pymssql(MSDialect):
+    supports_native_decimal = True
+    driver = "pymssql"
+
+    preparer = MSIdentifierPreparer_pymssql
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {sqltypes.Numeric: _MSNumeric_pymssql, sqltypes.Float: sqltypes.Float},
+    )
+
+    @classmethod
+    def dbapi(cls):
+        module = __import__("pymssql")
+        # pymmsql < 2.1.1 doesn't have a Binary method.  we use string
+        client_ver = tuple(int(x) for x in module.__version__.split("."))
+        if client_ver < (2, 1, 1):
+            # TODO: monkeypatching here is less than ideal
+            module.Binary = lambda x: x if hasattr(x, "decode") else str(x)
+
+        if client_ver < (1,):
+            util.warn(
+                "The pymssql dialect expects at least "
+                "the 1.0 series of the pymssql DBAPI."
+            )
+        return module
+
+    def _get_server_version_info(self, connection):
+        vers = connection.scalar("select @@version")
+        m = re.match(r"Microsoft .*? - (\d+).(\d+).(\d+).(\d+)", vers)
+        if m:
+            return tuple(int(x) for x in m.group(1, 2, 3, 4))
+        else:
+            return None
+
+    def create_connect_args(self, url):
+        opts = url.translate_connect_args(username="user")
+        opts.update(url.query)
+        port = opts.pop("port", None)
+        if port and "host" in opts:
+            opts["host"] = "%s:%s" % (opts["host"], port)
+        return [[], opts]
+
+    def is_disconnect(self, e, connection, cursor):
+        for msg in (
+            "Adaptive Server connection timed out",
+            "Net-Lib error during Connection reset by peer",
+            "message 20003",  # connection timeout
+            "Error 10054",
+            "Not connected to any MS SQL server",
+            "Connection is closed",
+            "message 20006",  # Write to the server failed
+            "message 20017",  # Unexpected EOF from the server
+            "message 20047",  # DBPROCESS is dead or not enabled
+        ):
+            if msg in str(e):
+                return True
+        else:
+            return False
+
+    def set_isolation_level(self, connection, level):
+        if level == "AUTOCOMMIT":
+            connection.autocommit(True)
+        else:
+            connection.autocommit(False)
+            super(MSDialect_pymssql, self).set_isolation_level(
+                connection, level
+            )
+
+
+dialect = MSDialect_pymssql

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/pyodbc.py

@@ -0,0 +1,375 @@
+# mssql/pyodbc.py
+# Copyright (C) 2005-2019 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
+
+r"""
+.. dialect:: mssql+pyodbc
+    :name: PyODBC
+    :dbapi: pyodbc
+    :connectstring: mssql+pyodbc://<username>:<password>@<dsnname>
+    :url: http://pypi.python.org/pypi/pyodbc/
+
+Connecting to PyODBC
+--------------------
+
+The URL here is to be translated to PyODBC connection strings, as
+detailed in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_.
+
+DSN Connections
+^^^^^^^^^^^^^^^
+
+A DSN connection in ODBC means that a pre-existing ODBC datasource is
+configured on the client machine.   The application then specifies the name
+of this datasource, which encompasses details such as the specific ODBC driver
+in use as well as the network address of the database.   Assuming a datasource
+is configured on the client, a basic DSN-based connection looks like::
+
+    engine = create_engine("mssql+pyodbc://scott:tiger@some_dsn")
+
+Which above, will pass the following connection string to PyODBC::
+
+    dsn=mydsn;UID=user;PWD=pass
+
+If the username and password are omitted, the DSN form will also add
+the ``Trusted_Connection=yes`` directive to the ODBC string.
+
+Hostname Connections
+^^^^^^^^^^^^^^^^^^^^
+
+Hostname-based connections are also supported by pyodbc.  These are often
+easier to use than a DSN and have the additional advantage that the specific
+database name to connect towards may be specified locally in the URL, rather
+than it being fixed as part of a datasource configuration.
+
+When using a hostname connection, the driver name must also be specified in the
+query parameters of the URL.  As these names usually have spaces in them, the
+name must be URL encoded which means using plus signs for spaces::
+
+    engine = create_engine("mssql+pyodbc://scott:tiger@myhost:port/databasename?driver=SQL+Server+Native+Client+10.0")
+
+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``.
+
+Pass through exact Pyodbc string
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A PyODBC connection string can also be sent in pyodbc's format directly, 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 encoded, as
+illustrated below using ``urllib.parse.quote_plus``::
+
+    import urllib
+    params = urllib.parse.quote_plus("DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password")
+
+    engine = create_engine("mssql+pyodbc:///?odbc_connect=%s" % params)
+
+
+Driver / Unicode Support
+-------------------------
+
+PyODBC works best with Microsoft ODBC drivers, particularly in the area
+of Unicode support on both Python 2 and Python 3.
+
+Using the FreeTDS ODBC drivers on Linux or OSX with PyODBC is **not**
+recommended; there have been historically many Unicode-related issues
+in this area, including before Microsoft offered ODBC drivers for Linux
+and OSX.   Now that Microsoft offers drivers for all platforms, for
+PyODBC support these are recommended.  FreeTDS remains relevant for
+non-ODBC drivers such as pymssql where it works very well.
+
+
+Rowcount Support
+----------------
+
+Pyodbc only has partial support for rowcount.  See the notes at
+:ref:`mssql_rowcount_versioning` for important notes when using ORM
+versioning.
+
+.. _mssql_pyodbc_fastexecutemany:
+
+Fast Executemany Mode
+---------------------
+
+The Pyodbc driver has added support for a "fast executemany" mode of execution
+which greatly reduces round trips for a DBAPI ``executemany()`` call when using
+Microsoft ODBC drivers.  The feature is enabled by setting the flag
+``.fast_executemany`` on the DBAPI cursor when an executemany call is to be
+used.   The SQLAlchemy pyodbc SQL Server dialect supports setting this flag
+automatically when the ``.fast_executemany`` flag is passed to
+:func:`.create_engine`; note that the ODBC driver must be the Microsoft driver
+in order to use this flag::
+
+    engine = create_engine(
+        "mssql+pyodbc://scott:tiger@mssql2017:1433/test?driver=ODBC+Driver+13+for+SQL+Server",
+        fast_executemany=True)
+
+.. versionadded:: 1.3
+
+.. seealso::
+
+    `fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_
+    - on github
+
+
+"""  # noqa
+
+import decimal
+import re
+
+from .base import BINARY
+from .base import MSDialect
+from .base import MSExecutionContext
+from .base import VARBINARY
+from ... import exc
+from ... import types as sqltypes
+from ... import util
+from ...connectors.pyodbc import PyODBCConnector
+
+
+class _ms_numeric_pyodbc(object):
+
+    """Turns Decimals with adjusted() < 0 or > 7 into strings.
+
+    The routines here are needed for older pyodbc versions
+    as well as current mxODBC versions.
+
+    """
+
+    def bind_processor(self, 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)
+                elif adjusted > 7:
+                    return self._large_dec_to_string(value)
+
+            if super_process:
+                return super_process(value)
+            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.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 _int]),
+                "0" * (value.adjusted() - (len(_int) - 1)),
+            )
+        else:
+            if (len(_int) - 1) > value.adjusted():
+                result = "%s%s.%s" % (
+                    (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 _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 _ms_binary_pyodbc(object):
+    """Wraps binary values in dialect-specific Binary wrapper.
+    If the value is null, return a pyodbc-specific BinaryNull
+    object to prevent pyODBC [and FreeTDS] from defaulting binary
+    NULL types to SQLWCHAR and causing implicit conversion errors.
+    """
+
+    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 _VARBINARY_pyodbc(_ms_binary_pyodbc, VARBINARY):
+    pass
+
+
+class _BINARY_pyodbc(_ms_binary_pyodbc, BINARY):
+    pass
+
+
+class MSExecutionContext_pyodbc(MSExecutionContext):
+    _embedded_scope_identity = False
+
+    def pre_exec(self):
+        """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"
+        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.)
+            while True:
+                try:
+                    # fetchall() ensures the cursor is consumed
+                    # without closing it (FreeTDS particularly)
+                    row = self.cursor.fetchall()[0]
+                    break
+                except self.dialect.dbapi.Error:
+                    # 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()
+
+
+class MSDialect_pyodbc(PyODBCConnector, MSDialect):
+
+    execution_ctx_cls = MSExecutionContext_pyodbc
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {
+            sqltypes.Numeric: _MSNumeric_pyodbc,
+            sqltypes.Float: _MSFloat_pyodbc,
+            BINARY: _BINARY_pyodbc,
+            # SQL Server dialect has a VARBINARY that is just to support
+            # "deprecate_large_types" w/ VARBINARY(max), but also we must
+            # handle the usual SQL standard VARBINARY
+            VARBINARY: _VARBINARY_pyodbc,
+            sqltypes.VARBINARY: _VARBINARY_pyodbc,
+            sqltypes.LargeBinary: _VARBINARY_pyodbc,
+        },
+    )
+
+    def __init__(
+        self, description_encoding=None, fast_executemany=False, **params
+    ):
+        if "description_encoding" in params:
+            self.description_encoding = params.pop("description_encoding")
+        super(MSDialect_pyodbc, self).__init__(**params)
+        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,
+        )
+        self.fast_executemany = fast_executemany
+
+    def _get_server_version_info(self, connection):
+        try:
+            # "Version of the instance of SQL Server, in the form
+            # of 'major.minor.build.revision'"
+            raw = connection.scalar(
+                "SELECT CAST(SERVERPROPERTY('ProductVersion') AS VARCHAR)"
+            )
+        except exc.DBAPIError:
+            # SQL Server docs indicate this function isn't present prior to
+            # 2008.  Before we had the VARCHAR cast above, pyodbc would also
+            # fail on this query.
+            return super(MSDialect_pyodbc, self)._get_server_version_info(
+                connection, allow_chars=False
+            )
+        else:
+            version = []
+            r = re.compile(r"[.\-]")
+            for n in r.split(raw):
+                try:
+                    version.append(int(n))
+                except ValueError:
+                    pass
+            return tuple(version)
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        if self.fast_executemany:
+            cursor.fast_executemany = True
+        super(MSDialect_pyodbc, self).do_executemany(
+            cursor, statement, parameters, context=context
+        )
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.Error):
+            for code in (
+                "08S01",
+                "01002",
+                "08003",
+                "08007",
+                "08S02",
+                "08001",
+                "HYT00",
+                "HY010",
+                "10054",
+            ):
+                if code in str(e):
+                    return True
+        return super(MSDialect_pyodbc, self).is_disconnect(
+            e, connection, cursor
+        )
+
+
+dialect = MSDialect_pyodbc

venv/lib/python3.7/site-packages/sqlalchemy/dialects/mssql/zxjdbc.py

@@ -0,0 +1,71 @@
+# mssql/zxjdbc.py
+# Copyright (C) 2005-2019 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
+
+"""
+.. dialect:: mssql+zxjdbc
+    :name: zxJDBC for Jython
+    :dbapi: zxjdbc
+    :connectstring: mssql+zxjdbc://user:pass@host:port/dbname[?key=value&key=value...]
+    :driverurl: http://jtds.sourceforge.net/
+
+    .. note:: Jython is not supported by current versions of SQLAlchemy.  The
+       zxjdbc dialect should be considered as experimental.
+
+"""  # noqa
+from .base import MSDialect
+from .base import MSExecutionContext
+from ... import engine
+from ...connectors.zxJDBC import ZxJDBCConnector
+
+
+class MSExecutionContext_zxjdbc(MSExecutionContext):
+
+    _embedded_scope_identity = False
+
+    def pre_exec(self):
+        super(MSExecutionContext_zxjdbc, self).pre_exec()
+        # scope_identity after the fact returns null in jTDS so we must
+        # embed it
+        if self._select_lastrowid and self.dialect.use_scope_identity:
+            self._embedded_scope_identity = True
+            self.statement += "; SELECT scope_identity()"
+
+    def post_exec(self):
+        if self._embedded_scope_identity:
+            while True:
+                try:
+                    row = self.cursor.fetchall()[0]
+                    break
+                except self.dialect.dbapi.Error:
+                    self.cursor.nextset()
+            self._lastrowid = int(row[0])
+
+        if (
+            self.isinsert or self.isupdate or self.isdelete
+        ) and self.compiled.returning:
+            self._result_proxy = engine.FullyBufferedResultProxy(self)
+
+        if self._enable_identity_insert:
+            table = self.dialect.identifier_preparer.format_table(
+                self.compiled.statement.table
+            )
+            self.cursor.execute("SET IDENTITY_INSERT %s OFF" % table)
+
+
+class MSDialect_zxjdbc(ZxJDBCConnector, MSDialect):
+    jdbc_db_name = "jtds:sqlserver"
+    jdbc_driver_name = "net.sourceforge.jtds.jdbc.Driver"
+
+    execution_ctx_cls = MSExecutionContext_zxjdbc
+
+    def _get_server_version_info(self, connection):
+        return tuple(
+            int(x) for x in connection.connection.dbversion.split(".")
+        )
+
+
+dialect = MSDialect_zxjdbc