Update 2025-04-24_11:44:19

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/__init__.py

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+# dialects/mssql/__init__.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+from . import aioodbc  # noqa
+from . import base  # noqa
+from . import pymssql  # noqa
+from . import pyodbc  # 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 DOUBLE_PRECISION
+from .base import FLOAT
+from .base import IMAGE
+from .base import INTEGER
+from .base import JSON
+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 UNIQUEIDENTIFIER
+from .base import VARBINARY
+from .base import VARCHAR
+from .base import XML
+from ...sql import try_cast
+
+
+base.dialect = dialect = pyodbc.dialect
+
+
+__all__ = (
+    "JSON",
+    "INTEGER",
+    "BIGINT",
+    "SMALLINT",
+    "TINYINT",
+    "VARCHAR",
+    "NVARCHAR",
+    "CHAR",
+    "NCHAR",
+    "TEXT",
+    "NTEXT",
+    "DECIMAL",
+    "NUMERIC",
+    "FLOAT",
+    "DATETIME",
+    "DATETIME2",
+    "DATETIMEOFFSET",
+    "DATE",
+    "DOUBLE_PRECISION",
+    "TIME",
+    "SMALLDATETIME",
+    "BINARY",
+    "VARBINARY",
+    "BIT",
+    "REAL",
+    "IMAGE",
+    "TIMESTAMP",
+    "ROWVERSION",
+    "MONEY",
+    "SMALLMONEY",
+    "UNIQUEIDENTIFIER",
+    "SQL_VARIANT",
+    "XML",
+    "dialect",
+    "try_cast",
+)

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/aioodbc.py

@@ -0,0 +1,63 @@
+# dialects/mssql/aioodbc.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+r"""
+.. dialect:: mssql+aioodbc
+    :name: aioodbc
+    :dbapi: aioodbc
+    :connectstring: mssql+aioodbc://<username>:<password>@<dsnname>
+    :url: https://pypi.org/project/aioodbc/
+
+
+Support for the SQL Server database in asyncio style, using the aioodbc
+driver which itself is a thread-wrapper around pyodbc.
+
+.. versionadded:: 2.0.23  Added the mssql+aioodbc dialect which builds
+   on top of the pyodbc and general aio* dialect architecture.
+
+Using a special asyncio mediation layer, the aioodbc dialect is usable
+as the backend for the :ref:`SQLAlchemy asyncio <asyncio_toplevel>`
+extension package.
+
+Most behaviors and caveats for this driver are the same as that of the
+pyodbc dialect used on SQL Server; see :ref:`mssql_pyodbc` for general
+background.
+
+This dialect should normally be used only with the
+:func:`_asyncio.create_async_engine` engine creation function; connection
+styles are otherwise equivalent to those documented in the pyodbc section::
+
+    from sqlalchemy.ext.asyncio import create_async_engine
+
+    engine = create_async_engine(
+        "mssql+aioodbc://scott:tiger@mssql2017:1433/test?"
+        "driver=ODBC+Driver+18+for+SQL+Server&TrustServerCertificate=yes"
+    )
+
+"""
+
+from __future__ import annotations
+
+from .pyodbc import MSDialect_pyodbc
+from .pyodbc import MSExecutionContext_pyodbc
+from ...connectors.aioodbc import aiodbcConnector
+
+
+class MSExecutionContext_aioodbc(MSExecutionContext_pyodbc):
+    def create_server_side_cursor(self):
+        return self._dbapi_connection.cursor(server_side=True)
+
+
+class MSDialectAsync_aioodbc(aiodbcConnector, MSDialect_pyodbc):
+    driver = "aioodbc"
+
+    supports_statement_cache = True
+
+    execution_ctx_cls = MSExecutionContext_aioodbc
+
+
+dialect = MSDialectAsync_aioodbc

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/information_schema.py

@@ -0,0 +1,254 @@
+# dialects/mssql/information_schema.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+from ... import cast
+from ... import Column
+from ... import MetaData
+from ... import Table
+from ...ext.compiler import compiles
+from ...sql import expression
+from ...types import Boolean
+from ...types import Integer
+from ...types import Numeric
+from ...types import NVARCHAR
+from ...types import String
+from ...types import TypeDecorator
+from ...types import Unicode
+
+
+ischema = MetaData()
+
+
+class CoerceUnicode(TypeDecorator):
+    impl = Unicode
+    cache_ok = True
+
+    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",
+)
+
+mssql_temp_table_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="tempdb.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",
+)
+
+computed_columns = Table(
+    "computed_columns",
+    ischema,
+    Column("object_id", Integer),
+    Column("name", CoerceUnicode),
+    Column("is_computed", Boolean),
+    Column("is_persisted", Boolean),
+    Column("definition", CoerceUnicode),
+    schema="sys",
+)
+
+sequences = Table(
+    "SEQUENCES",
+    ischema,
+    Column("SEQUENCE_CATALOG", CoerceUnicode, key="sequence_catalog"),
+    Column("SEQUENCE_SCHEMA", CoerceUnicode, key="sequence_schema"),
+    Column("SEQUENCE_NAME", CoerceUnicode, key="sequence_name"),
+    schema="INFORMATION_SCHEMA",
+)
+
+
+class NumericSqlVariant(TypeDecorator):
+    r"""This type casts sql_variant columns in the identity_columns view
+    to numeric. This is required because:
+
+    * pyodbc does not support sql_variant
+    * pymssql under python 2 return the byte representation of the number,
+      int 1 is returned as "\x01\x00\x00\x00". On python 3 it returns the
+      correct value as string.
+    """
+
+    impl = Unicode
+    cache_ok = True
+
+    def column_expression(self, colexpr):
+        return cast(colexpr, Numeric(38, 0))
+
+
+identity_columns = Table(
+    "identity_columns",
+    ischema,
+    Column("object_id", Integer),
+    Column("name", CoerceUnicode),
+    Column("is_identity", Boolean),
+    Column("seed_value", NumericSqlVariant),
+    Column("increment_value", NumericSqlVariant),
+    Column("last_value", NumericSqlVariant),
+    Column("is_not_for_replication", Boolean),
+    schema="sys",
+)
+
+
+class NVarcharSqlVariant(TypeDecorator):
+    """This type casts sql_variant columns in the extended_properties view
+    to nvarchar. This is required because pyodbc does not support sql_variant
+    """
+
+    impl = Unicode
+    cache_ok = True
+
+    def column_expression(self, colexpr):
+        return cast(colexpr, NVARCHAR)
+
+
+extended_properties = Table(
+    "extended_properties",
+    ischema,
+    Column("class", Integer),  # TINYINT
+    Column("class_desc", CoerceUnicode),
+    Column("major_id", Integer),
+    Column("minor_id", Integer),
+    Column("name", CoerceUnicode),
+    Column("value", NVarcharSqlVariant),
+    schema="sys",
+)

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/json.py

@@ -0,0 +1,129 @@
+# dialects/mssql/json.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+from ... import types as sqltypes
+
+# technically, all the dialect-specific datatypes that don't have any special
+# behaviors would be private with names like _MSJson. However, we haven't been
+# doing this for mysql.JSON or sqlite.JSON which both have JSON / JSONIndexType
+# / JSONPathType in their json.py files, so keep consistent with that
+# sub-convention for now.  A future change can update them all to be
+# package-private at once.
+
+
+class JSON(sqltypes.JSON):
+    """MSSQL JSON type.
+
+    MSSQL supports JSON-formatted data as of SQL Server 2016.
+
+    The :class:`_mssql.JSON` datatype at the DDL level will represent the
+    datatype as ``NVARCHAR(max)``, but provides for JSON-level comparison
+    functions as well as Python coercion behavior.
+
+    :class:`_mssql.JSON` is used automatically whenever the base
+    :class:`_types.JSON` datatype is used against a SQL Server backend.
+
+    .. seealso::
+
+        :class:`_types.JSON` - main documentation for the generic
+        cross-platform JSON datatype.
+
+    The :class:`_mssql.JSON` type supports persistence of JSON values
+    as well as the core index operations provided by :class:`_types.JSON`
+    datatype, by adapting the operations to render the ``JSON_VALUE``
+    or ``JSON_QUERY`` functions at the database level.
+
+    The SQL Server :class:`_mssql.JSON` type necessarily makes use of the
+    ``JSON_QUERY`` and ``JSON_VALUE`` functions when querying for elements
+    of a JSON object.   These two functions have a major restriction in that
+    they are **mutually exclusive** based on the type of object to be returned.
+    The ``JSON_QUERY`` function **only** returns a JSON dictionary or list,
+    but not an individual string, numeric, or boolean element; the
+    ``JSON_VALUE`` function **only** returns an individual string, numeric,
+    or boolean element.   **both functions either return NULL or raise
+    an error if they are not used against the correct expected value**.
+
+    To handle this awkward requirement, indexed access rules are as follows:
+
+    1. When extracting a sub element from a JSON that is itself a JSON
+       dictionary or list, the :meth:`_types.JSON.Comparator.as_json` accessor
+       should be used::
+
+            stmt = select(data_table.c.data["some key"].as_json()).where(
+                data_table.c.data["some key"].as_json() == {"sub": "structure"}
+            )
+
+    2. When extracting a sub element from a JSON that is a plain boolean,
+       string, integer, or float, use the appropriate method among
+       :meth:`_types.JSON.Comparator.as_boolean`,
+       :meth:`_types.JSON.Comparator.as_string`,
+       :meth:`_types.JSON.Comparator.as_integer`,
+       :meth:`_types.JSON.Comparator.as_float`::
+
+            stmt = select(data_table.c.data["some key"].as_string()).where(
+                data_table.c.data["some key"].as_string() == "some string"
+            )
+
+    .. versionadded:: 1.4
+
+
+    """
+
+    # note there was a result processor here that was looking for "number",
+    # but none of the tests seem to exercise it.
+
+
+# Note: these objects currently match exactly those of MySQL, however since
+# these are not generalizable to all JSON implementations, remain separately
+# implemented for each dialect.
+class _FormatTypeMixin:
+    def _format_value(self, value):
+        raise NotImplementedError()
+
+    def bind_processor(self, dialect):
+        super_proc = self.string_bind_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+    def literal_processor(self, dialect):
+        super_proc = self.string_literal_processor(dialect)
+
+        def process(value):
+            value = self._format_value(value)
+            if super_proc:
+                value = super_proc(value)
+            return value
+
+        return process
+
+
+class JSONIndexType(_FormatTypeMixin, sqltypes.JSON.JSONIndexType):
+    def _format_value(self, value):
+        if isinstance(value, int):
+            value = "$[%s]" % value
+        else:
+            value = '$."%s"' % value
+        return value
+
+
+class JSONPathType(_FormatTypeMixin, sqltypes.JSON.JSONPathType):
+    def _format_value(self, value):
+        return "$%s" % (
+            "".join(
+                [
+                    "[%s]" % elem if isinstance(elem, int) else '."%s"' % elem
+                    for elem in value
+                ]
+            )
+        )

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/provision.py

@@ -0,0 +1,162 @@
+# dialects/mssql/provision.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+from sqlalchemy import inspect
+from sqlalchemy import Integer
+from ... import create_engine
+from ... import exc
+from ...schema import Column
+from ...schema import DropConstraint
+from ...schema import ForeignKeyConstraint
+from ...schema import MetaData
+from ...schema import Table
+from ...testing.provision import create_db
+from ...testing.provision import drop_all_schema_objects_pre_tables
+from ...testing.provision import drop_db
+from ...testing.provision import generate_driver_url
+from ...testing.provision import get_temp_table_name
+from ...testing.provision import log
+from ...testing.provision import normalize_sequence
+from ...testing.provision import post_configure_engine
+from ...testing.provision import run_reap_dbs
+from ...testing.provision import temp_table_keyword_args
+
+
+@post_configure_engine.for_db("mssql")
+def post_configure_engine(url, engine, follower_ident):
+    if engine.driver == "pyodbc":
+        engine.dialect.dbapi.pooling = False
+
+
+@generate_driver_url.for_db("mssql")
+def generate_driver_url(url, driver, query_str):
+    backend = url.get_backend_name()
+
+    new_url = url.set(drivername="%s+%s" % (backend, driver))
+
+    if driver not in ("pyodbc", "aioodbc"):
+        new_url = new_url.set(query="")
+
+    if driver == "aioodbc":
+        new_url = new_url.update_query_dict({"MARS_Connection": "Yes"})
+
+    if query_str:
+        new_url = new_url.update_query_string(query_str)
+
+    try:
+        new_url.get_dialect()
+    except exc.NoSuchModuleError:
+        return None
+    else:
+        return new_url
+
+
+@create_db.for_db("mssql")
+def _mssql_create_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        conn.exec_driver_sql("create database %s" % ident)
+        conn.exec_driver_sql(
+            "ALTER DATABASE %s SET ALLOW_SNAPSHOT_ISOLATION ON" % ident
+        )
+        conn.exec_driver_sql(
+            "ALTER DATABASE %s SET READ_COMMITTED_SNAPSHOT ON" % ident
+        )
+        conn.exec_driver_sql("use %s" % ident)
+        conn.exec_driver_sql("create schema test_schema")
+        conn.exec_driver_sql("create schema test_schema_2")
+
+
+@drop_db.for_db("mssql")
+def _mssql_drop_db(cfg, eng, ident):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        _mssql_drop_ignore(conn, ident)
+
+
+def _mssql_drop_ignore(conn, ident):
+    try:
+        # typically when this happens, we can't KILL the session anyway,
+        # so let the cleanup process drop the DBs
+        # for row in conn.exec_driver_sql(
+        #     "select session_id from sys.dm_exec_sessions "
+        #        "where database_id=db_id('%s')" % ident):
+        #    log.info("killing SQL server session %s", row['session_id'])
+        #    conn.exec_driver_sql("kill %s" % row['session_id'])
+        conn.exec_driver_sql("drop database %s" % ident)
+        log.info("Reaped db: %s", ident)
+        return True
+    except exc.DatabaseError as err:
+        log.warning("couldn't drop db: %s", err)
+        return False
+
+
+@run_reap_dbs.for_db("mssql")
+def _reap_mssql_dbs(url, idents):
+    log.info("db reaper connecting to %r", url)
+    eng = create_engine(url)
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        log.info("identifiers in file: %s", ", ".join(idents))
+
+        to_reap = conn.exec_driver_sql(
+            "select d.name from sys.databases as d where name "
+            "like 'TEST_%' and not exists (select session_id "
+            "from sys.dm_exec_sessions "
+            "where database_id=d.database_id)"
+        )
+        all_names = {dbname.lower() for (dbname,) in to_reap}
+        to_drop = set()
+        for name in all_names:
+            if name in idents:
+                to_drop.add(name)
+
+        dropped = total = 0
+        for total, dbname in enumerate(to_drop, 1):
+            if _mssql_drop_ignore(conn, dbname):
+                dropped += 1
+        log.info(
+            "Dropped %d out of %d stale databases detected", dropped, total
+        )
+
+
+@temp_table_keyword_args.for_db("mssql")
+def _mssql_temp_table_keyword_args(cfg, eng):
+    return {}
+
+
+@get_temp_table_name.for_db("mssql")
+def _mssql_get_temp_table_name(cfg, eng, base_name):
+    return "##" + base_name
+
+
+@drop_all_schema_objects_pre_tables.for_db("mssql")
+def drop_all_schema_objects_pre_tables(cfg, eng):
+    with eng.connect().execution_options(isolation_level="AUTOCOMMIT") as conn:
+        inspector = inspect(conn)
+        for schema in (None, "dbo", cfg.test_schema, cfg.test_schema_2):
+            for tname in inspector.get_table_names(schema=schema):
+                tb = Table(
+                    tname,
+                    MetaData(),
+                    Column("x", Integer),
+                    Column("y", Integer),
+                    schema=schema,
+                )
+                for fk in inspect(conn).get_foreign_keys(tname, schema=schema):
+                    conn.execute(
+                        DropConstraint(
+                            ForeignKeyConstraint(
+                                [tb.c.x], [tb.c.y], name=fk["name"]
+                            )
+                        )
+                    )
+
+
+@normalize_sequence.for_db("mssql")
+def normalize_sequence(cfg, sequence):
+    if sequence.start is None:
+        sequence.start = 1
+    return sequence

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/pymssql.py

@@ -0,0 +1,126 @@
+# dialects/mssql/pymssql.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+
+"""
+.. dialect:: mssql+pymssql
+    :name: pymssql
+    :dbapi: pymssql
+    :connectstring: mssql+pymssql://<username>:<password>@<freetds_name>/?charset=utf8
+
+pymssql is a Python module that provides a Python DBAPI interface around
+`FreeTDS <https://www.freetds.org/>`_.
+
+.. versionchanged:: 2.0.5
+
+    pymssql was restored to SQLAlchemy's continuous integration testing
+
+
+"""  # noqa
+import re
+
+from .base import MSDialect
+from .base import MSIdentifierPreparer
+from ... import types as sqltypes
+from ... import util
+from ...engine import processors
+
+
+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().__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_statement_cache = True
+    supports_native_decimal = True
+    supports_native_uuid = True
+    driver = "pymssql"
+
+    preparer = MSIdentifierPreparer_pymssql
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {sqltypes.Numeric: _MSNumeric_pymssql, sqltypes.Float: sqltypes.Float},
+    )
+
+    @classmethod
+    def import_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.exec_driver_sql("select @@version").scalar()
+        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
+            "The server failed to resume the transaction",
+        ):
+            if msg in str(e):
+                return True
+        else:
+            return False
+
+    def get_isolation_level_values(self, dbapi_connection):
+        return super().get_isolation_level_values(dbapi_connection) + [
+            "AUTOCOMMIT"
+        ]
+
+    def set_isolation_level(self, dbapi_connection, level):
+        if level == "AUTOCOMMIT":
+            dbapi_connection.autocommit(True)
+        else:
+            dbapi_connection.autocommit(False)
+            super().set_isolation_level(dbapi_connection, level)
+
+
+dialect = MSDialect_pymssql

venv/lib/python3.11/site-packages/sqlalchemy/dialects/mssql/pyodbc.py

@@ -0,0 +1,760 @@
+# dialects/mssql/pyodbc.py
+# Copyright (C) 2005-2025 the SQLAlchemy authors and contributors
+# <see AUTHORS file>
+#
+# This module is part of SQLAlchemy and is released under
+# the MIT License: https://www.opensource.org/licenses/mit-license.php
+# mypy: ignore-errors
+
+r"""
+.. dialect:: mssql+pyodbc
+    :name: PyODBC
+    :dbapi: pyodbc
+    :connectstring: mssql+pyodbc://<username>:<password>@<dsnname>
+    :url: https://pypi.org/project/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:
+
+.. sourcecode:: text
+
+    DSN=some_dsn;UID=scott;PWD=tiger
+
+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=ODBC+Driver+17+for+SQL+Server"
+    )
+
+The ``driver`` keyword is significant to the pyodbc dialect and must be
+specified in lowercase.
+
+Any other names passed in the query string are passed through in the pyodbc
+connect string, such as ``authentication``, ``TrustServerCertificate``, etc.
+Multiple keyword arguments must be separated by an ampersand (``&``); these
+will be translated to semicolons when the pyodbc connect string is generated
+internally::
+
+    e = create_engine(
+        "mssql+pyodbc://scott:tiger@mssql2017:1433/test?"
+        "driver=ODBC+Driver+18+for+SQL+Server&TrustServerCertificate=yes"
+        "&authentication=ActiveDirectoryIntegrated"
+    )
+
+The equivalent URL can be constructed using :class:`_sa.engine.URL`::
+
+    from sqlalchemy.engine import URL
+
+    connection_url = URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="mssql2017",
+        port=1433,
+        database="test",
+        query={
+            "driver": "ODBC Driver 18 for SQL Server",
+            "TrustServerCertificate": "yes",
+            "authentication": "ActiveDirectoryIntegrated",
+        },
+    )
+
+Pass through exact Pyodbc string
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A PyODBC connection string can also be sent in pyodbc's format directly, as
+specified in `the PyODBC documentation
+<https://github.com/mkleehammer/pyodbc/wiki/Connecting-to-databases>`_,
+using the parameter ``odbc_connect``.  A :class:`_sa.engine.URL` object
+can help make this easier::
+
+    from sqlalchemy.engine import URL
+
+    connection_string = "DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password"
+    connection_url = URL.create(
+        "mssql+pyodbc", query={"odbc_connect": connection_string}
+    )
+
+    engine = create_engine(connection_url)
+
+.. _mssql_pyodbc_access_tokens:
+
+Connecting to databases with access tokens
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Some database servers are set up to only accept access tokens for login. For
+example, SQL Server allows the use of Azure Active Directory tokens to connect
+to databases. This requires creating a credential object using the
+``azure-identity`` library. More information about the authentication step can be
+found in `Microsoft's documentation
+<https://docs.microsoft.com/en-us/azure/developer/python/azure-sdk-authenticate?tabs=bash>`_.
+
+After getting an engine, the credentials need to be sent to ``pyodbc.connect``
+each time a connection is requested. One way to do this is to set up an event
+listener on the engine that adds the credential token to the dialect's connect
+call. This is discussed more generally in :ref:`engines_dynamic_tokens`. For
+SQL Server in particular, this is passed as an ODBC connection attribute with
+a data structure `described by Microsoft
+<https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_.
+
+The following code snippet will create an engine that connects to an Azure SQL
+database using Azure credentials::
+
+    import struct
+    from sqlalchemy import create_engine, event
+    from sqlalchemy.engine.url import URL
+    from azure import identity
+
+    # Connection option for access tokens, as defined in msodbcsql.h
+    SQL_COPT_SS_ACCESS_TOKEN = 1256
+    TOKEN_URL = "https://database.windows.net/"  # The token URL for any Azure SQL database
+
+    connection_string = "mssql+pyodbc://@my-server.database.windows.net/myDb?driver=ODBC+Driver+17+for+SQL+Server"
+
+    engine = create_engine(connection_string)
+
+    azure_credentials = identity.DefaultAzureCredential()
+
+
+    @event.listens_for(engine, "do_connect")
+    def provide_token(dialect, conn_rec, cargs, cparams):
+        # remove the "Trusted_Connection" parameter that SQLAlchemy adds
+        cargs[0] = cargs[0].replace(";Trusted_Connection=Yes", "")
+
+        # create token credential
+        raw_token = azure_credentials.get_token(TOKEN_URL).token.encode(
+            "utf-16-le"
+        )
+        token_struct = struct.pack(
+            f"<I{len(raw_token)}s", len(raw_token), raw_token
+        )
+
+        # apply it to keyword arguments
+        cparams["attrs_before"] = {SQL_COPT_SS_ACCESS_TOKEN: token_struct}
+
+.. tip::
+
+    The ``Trusted_Connection`` token is currently added by the SQLAlchemy
+    pyodbc dialect when no username or password is present.  This needs
+    to be removed per Microsoft's
+    `documentation for Azure access tokens
+    <https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_,
+    stating that a connection string when using an access token must not contain
+    ``UID``, ``PWD``, ``Authentication`` or ``Trusted_Connection`` parameters.
+
+.. _azure_synapse_ignore_no_transaction_on_rollback:
+
+Avoiding transaction-related exceptions on Azure Synapse Analytics
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Azure Synapse Analytics has a significant difference in its transaction
+handling compared to plain SQL Server; in some cases an error within a Synapse
+transaction can cause it to be arbitrarily terminated on the server side, which
+then causes the DBAPI ``.rollback()`` method (as well as ``.commit()``) to
+fail. The issue prevents the usual DBAPI contract of allowing ``.rollback()``
+to pass silently if no transaction is present as the driver does not expect
+this condition. The symptom of this failure is an exception with a message
+resembling 'No corresponding transaction found. (111214)' when attempting to
+emit a ``.rollback()`` after an operation had a failure of some kind.
+
+This specific case can be handled by passing ``ignore_no_transaction_on_rollback=True`` to
+the SQL Server dialect via the :func:`_sa.create_engine` function as follows::
+
+    engine = create_engine(
+        connection_url, ignore_no_transaction_on_rollback=True
+    )
+
+Using the above parameter, the dialect will catch ``ProgrammingError``
+exceptions raised during ``connection.rollback()`` and emit a warning
+if the error message contains code ``111214``, however will not raise
+an exception.
+
+.. versionadded:: 1.4.40  Added the
+   ``ignore_no_transaction_on_rollback=True`` parameter.
+
+Enable autocommit for Azure SQL Data Warehouse (DW) connections
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Azure SQL Data Warehouse does not support transactions,
+and that can cause problems with SQLAlchemy's "autobegin" (and implicit
+commit/rollback) behavior. We can avoid these problems by enabling autocommit
+at both the pyodbc and engine levels::
+
+    connection_url = sa.engine.URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="dw.azure.example.com",
+        database="mydb",
+        query={
+            "driver": "ODBC Driver 17 for SQL Server",
+            "autocommit": "True",
+        },
+    )
+
+    engine = create_engine(connection_url).execution_options(
+        isolation_level="AUTOCOMMIT"
+    )
+
+Avoiding sending large string parameters as TEXT/NTEXT
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By default, for historical reasons, Microsoft's ODBC drivers for SQL Server
+send long string parameters (greater than 4000 SBCS characters or 2000 Unicode
+characters) as TEXT/NTEXT values. TEXT and NTEXT have been deprecated for many
+years and are starting to cause compatibility issues with newer versions of
+SQL_Server/Azure. For example, see `this
+issue <https://github.com/mkleehammer/pyodbc/issues/835>`_.
+
+Starting with ODBC Driver 18 for SQL Server we can override the legacy
+behavior and pass long strings as varchar(max)/nvarchar(max) using the
+``LongAsMax=Yes`` connection string parameter::
+
+    connection_url = sa.engine.URL.create(
+        "mssql+pyodbc",
+        username="scott",
+        password="tiger",
+        host="mssqlserver.example.com",
+        database="mydb",
+        query={
+            "driver": "ODBC Driver 18 for SQL Server",
+            "LongAsMax": "Yes",
+        },
+    )
+
+Pyodbc Pooling / connection close behavior
+------------------------------------------
+
+PyODBC uses internal `pooling
+<https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ by
+default, which means connections will be longer lived than they are within
+SQLAlchemy itself.  As SQLAlchemy has its own pooling behavior, it is often
+preferable to disable this behavior.  This behavior can only be disabled
+globally at the PyODBC module level, **before** any connections are made::
+
+    import pyodbc
+
+    pyodbc.pooling = False
+
+    # don't use the engine before pooling is set to False
+    engine = create_engine("mssql+pyodbc://user:pass@dsn")
+
+If this variable is left at its default value of ``True``, **the application
+will continue to maintain active database connections**, even when the
+SQLAlchemy engine itself fully discards a connection or if the engine is
+disposed.
+
+.. seealso::
+
+    `pooling <https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ -
+    in the PyODBC documentation.
+
+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
+----------------
+
+Previous limitations with the SQLAlchemy ORM's "versioned rows" feature with
+Pyodbc have been resolved as of SQLAlchemy 2.0.5. See the notes at
+:ref:`mssql_rowcount_versioning`.
+
+.. _mssql_pyodbc_fastexecutemany:
+
+Fast Executemany Mode
+---------------------
+
+The PyODBC driver includes support for a "fast executemany" mode of execution
+which greatly reduces round trips for a DBAPI ``executemany()`` call when using
+Microsoft ODBC drivers, for **limited size batches that fit in memory**.  The
+feature is enabled by setting the attribute ``.fast_executemany`` on the DBAPI
+cursor when an executemany call is to be used.   The SQLAlchemy PyODBC SQL
+Server dialect supports this parameter by passing the
+``fast_executemany`` parameter to
+:func:`_sa.create_engine` , when using the **Microsoft ODBC driver only**::
+
+    engine = create_engine(
+        "mssql+pyodbc://scott:tiger@mssql2017:1433/test?driver=ODBC+Driver+17+for+SQL+Server",
+        fast_executemany=True,
+    )
+
+.. versionchanged:: 2.0.9 - the ``fast_executemany`` parameter now has its
+   intended effect of this PyODBC feature taking effect for all INSERT
+   statements that are executed with multiple parameter sets, which don't
+   include RETURNING.  Previously, SQLAlchemy 2.0's :term:`insertmanyvalues`
+   feature would cause ``fast_executemany`` to not be used in most cases
+   even if specified.
+
+.. versionadded:: 1.3
+
+.. seealso::
+
+    `fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_
+    - on github
+
+.. _mssql_pyodbc_setinputsizes:
+
+Setinputsizes Support
+-----------------------
+
+As of version 2.0, the pyodbc ``cursor.setinputsizes()`` method is used for
+all statement executions, except for ``cursor.executemany()`` calls when
+fast_executemany=True where it is not supported (assuming
+:ref:`insertmanyvalues <engine_insertmanyvalues>` is kept enabled,
+"fastexecutemany" will not take place for INSERT statements in any case).
+
+The use of ``cursor.setinputsizes()`` can be disabled by passing
+``use_setinputsizes=False`` to :func:`_sa.create_engine`.
+
+When ``use_setinputsizes`` is left at its default of ``True``, the
+specific per-type symbols passed to ``cursor.setinputsizes()`` can be
+programmatically customized using the :meth:`.DialectEvents.do_setinputsizes`
+hook. See that method for usage examples.
+
+.. versionchanged:: 2.0  The mssql+pyodbc dialect now defaults to using
+   ``use_setinputsizes=True`` for all statement executions with the exception of
+   cursor.executemany() calls when fast_executemany=True.  The behavior can
+   be turned off by passing ``use_setinputsizes=False`` to
+   :func:`_sa.create_engine`.
+
+"""  # noqa
+
+
+import datetime
+import decimal
+import re
+import struct
+
+from .base import _MSDateTime
+from .base import _MSUnicode
+from .base import _MSUnicodeText
+from .base import BINARY
+from .base import DATETIMEOFFSET
+from .base import MSDialect
+from .base import MSExecutionContext
+from .base import VARBINARY
+from .json import JSON as _MSJson
+from .json import JSONIndexType as _MSJsonIndexType
+from .json import JSONPathType as _MSJsonPathType
+from ... import exc
+from ... import types as sqltypes
+from ... import util
+from ...connectors.pyodbc import PyODBCConnector
+from ...engine import cursor as _cursor
+
+
+class _ms_numeric_pyodbc:
+    """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().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:
+    """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 _ODBCDateTimeBindProcessor:
+    """Add bind processors to handle datetimeoffset behaviors"""
+
+    has_tz = False
+
+    def bind_processor(self, dialect):
+        def process(value):
+            if value is None:
+                return None
+            elif isinstance(value, str):
+                # if a string was passed directly, allow it through
+                return value
+            elif not value.tzinfo or (not self.timezone and not self.has_tz):
+                # for DateTime(timezone=False)
+                return value
+            else:
+                # for DATETIMEOFFSET or DateTime(timezone=True)
+                #
+                # Convert to string format required by T-SQL
+                dto_string = value.strftime("%Y-%m-%d %H:%M:%S.%f %z")
+                # offset needs a colon, e.g., -0700 -> -07:00
+                # "UTC offset in the form (+-)HHMM[SS[.ffffff]]"
+                # backend currently rejects seconds / fractional seconds
+                dto_string = re.sub(
+                    r"([\+\-]\d{2})([\d\.]+)$", r"\1:\2", dto_string
+                )
+                return dto_string
+
+        return process
+
+
+class _ODBCDateTime(_ODBCDateTimeBindProcessor, _MSDateTime):
+    pass
+
+
+class _ODBCDATETIMEOFFSET(_ODBCDateTimeBindProcessor, DATETIMEOFFSET):
+    has_tz = True
+
+
+class _VARBINARY_pyodbc(_ms_binary_pyodbc, VARBINARY):
+    pass
+
+
+class _BINARY_pyodbc(_ms_binary_pyodbc, BINARY):
+    pass
+
+
+class _String_pyodbc(sqltypes.String):
+    def get_dbapi_type(self, dbapi):
+        if self.length in (None, "max") or self.length >= 2000:
+            return (dbapi.SQL_VARCHAR, 0, 0)
+        else:
+            return dbapi.SQL_VARCHAR
+
+
+class _Unicode_pyodbc(_MSUnicode):
+    def get_dbapi_type(self, dbapi):
+        if self.length in (None, "max") or self.length >= 2000:
+            return (dbapi.SQL_WVARCHAR, 0, 0)
+        else:
+            return dbapi.SQL_WVARCHAR
+
+
+class _UnicodeText_pyodbc(_MSUnicodeText):
+    def get_dbapi_type(self, dbapi):
+        if self.length in (None, "max") or self.length >= 2000:
+            return (dbapi.SQL_WVARCHAR, 0, 0)
+        else:
+            return dbapi.SQL_WVARCHAR
+
+
+class _JSON_pyodbc(_MSJson):
+    def get_dbapi_type(self, dbapi):
+        return (dbapi.SQL_WVARCHAR, 0, 0)
+
+
+class _JSONIndexType_pyodbc(_MSJsonIndexType):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.SQL_WVARCHAR
+
+
+class _JSONPathType_pyodbc(_MSJsonPathType):
+    def get_dbapi_type(self, dbapi):
+        return dbapi.SQL_WVARCHAR
+
+
+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":
+        https://msdn.microsoft.com/en-us/library/ms190315.aspx
+
+        Background on why we attempt to embed "scope_identity()" into the same
+        statement as the INSERT:
+        https://code.google.com/p/pyodbc/wiki/FAQs#How_do_I_retrieve_autogenerated/identity_values?
+
+        """
+
+        super().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)
+                    rows = self.cursor.fetchall()
+                except self.dialect.dbapi.Error:
+                    # no way around this - nextset() consumes the previous set
+                    # so we need to just keep flipping
+                    self.cursor.nextset()
+                else:
+                    if not rows:
+                        # async adapter drivers just return None here
+                        self.cursor.nextset()
+                        continue
+                    row = rows[0]
+                    break
+
+            self._lastrowid = int(row[0])
+
+            self.cursor_fetch_strategy = _cursor._NO_CURSOR_DML
+        else:
+            super().post_exec()
+
+
+class MSDialect_pyodbc(PyODBCConnector, MSDialect):
+    supports_statement_cache = True
+
+    # note this parameter is no longer used by the ORM or default dialect
+    # see #9414
+    supports_sane_rowcount_returning = False
+
+    execution_ctx_cls = MSExecutionContext_pyodbc
+
+    colspecs = util.update_copy(
+        MSDialect.colspecs,
+        {
+            sqltypes.Numeric: _MSNumeric_pyodbc,
+            sqltypes.Float: _MSFloat_pyodbc,
+            BINARY: _BINARY_pyodbc,
+            # support DateTime(timezone=True)
+            sqltypes.DateTime: _ODBCDateTime,
+            DATETIMEOFFSET: _ODBCDATETIMEOFFSET,
+            # 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,
+            sqltypes.String: _String_pyodbc,
+            sqltypes.Unicode: _Unicode_pyodbc,
+            sqltypes.UnicodeText: _UnicodeText_pyodbc,
+            sqltypes.JSON: _JSON_pyodbc,
+            sqltypes.JSON.JSONIndexType: _JSONIndexType_pyodbc,
+            sqltypes.JSON.JSONPathType: _JSONPathType_pyodbc,
+            # this excludes Enum from the string/VARCHAR thing for now
+            # it looks like Enum's adaptation doesn't really support the
+            # String type itself having a dialect-level impl
+            sqltypes.Enum: sqltypes.Enum,
+        },
+    )
+
+    def __init__(
+        self,
+        fast_executemany=False,
+        use_setinputsizes=True,
+        **params,
+    ):
+        super().__init__(use_setinputsizes=use_setinputsizes, **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
+        if fast_executemany:
+            self.use_insertmanyvalues_wo_returning = False
+
+    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.exec_driver_sql(
+                "SELECT CAST(SERVERPROPERTY('ProductVersion') AS VARCHAR)"
+            ).scalar()
+        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()._get_server_version_info(connection)
+        else:
+            version = []
+            r = re.compile(r"[.\-]")
+            for n in r.split(raw):
+                try:
+                    version.append(int(n))
+                except ValueError:
+                    pass
+            return tuple(version)
+
+    def on_connect(self):
+        super_ = super().on_connect()
+
+        def on_connect(conn):
+            if super_ is not None:
+                super_(conn)
+
+            self._setup_timestampoffset_type(conn)
+
+        return on_connect
+
+    def _setup_timestampoffset_type(self, connection):
+        # output converter function for datetimeoffset
+        def _handle_datetimeoffset(dto_value):
+            tup = struct.unpack("<6hI2h", dto_value)
+            return datetime.datetime(
+                tup[0],
+                tup[1],
+                tup[2],
+                tup[3],
+                tup[4],
+                tup[5],
+                tup[6] // 1000,
+                datetime.timezone(
+                    datetime.timedelta(hours=tup[7], minutes=tup[8])
+                ),
+            )
+
+        odbc_SQL_SS_TIMESTAMPOFFSET = -155  # as defined in SQLNCLI.h
+        connection.add_output_converter(
+            odbc_SQL_SS_TIMESTAMPOFFSET, _handle_datetimeoffset
+        )
+
+    def do_executemany(self, cursor, statement, parameters, context=None):
+        if self.fast_executemany:
+            cursor.fast_executemany = True
+        super().do_executemany(cursor, statement, parameters, context=context)
+
+    def is_disconnect(self, e, connection, cursor):
+        if isinstance(e, self.dbapi.Error):
+            code = e.args[0]
+            if code in {
+                "08S01",
+                "01000",
+                "01002",
+                "08003",
+                "08007",
+                "08S02",
+                "08001",
+                "HYT00",
+                "HY010",
+                "10054",
+            }:
+                return True
+        return super().is_disconnect(e, connection, cursor)
+
+
+dialect = MSDialect_pyodbc