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746 lines
26 KiB
746 lines
26 KiB
1 year ago
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# mssql/pyodbc.py
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# Copyright (C) 2005-2023 the SQLAlchemy authors and contributors
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# <see AUTHORS file>
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#
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# This module is part of SQLAlchemy and is released under
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# the MIT License: https://www.opensource.org/licenses/mit-license.php
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# mypy: ignore-errors
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r"""
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.. dialect:: mssql+pyodbc
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:name: PyODBC
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:dbapi: pyodbc
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:connectstring: mssql+pyodbc://<username>:<password>@<dsnname>
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:url: https://pypi.org/project/pyodbc/
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Connecting to PyODBC
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--------------------
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The URL here is to be translated to PyODBC connection strings, as
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detailed in `ConnectionStrings <https://code.google.com/p/pyodbc/wiki/ConnectionStrings>`_.
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DSN Connections
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^^^^^^^^^^^^^^^
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A DSN connection in ODBC means that a pre-existing ODBC datasource is
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configured on the client machine. The application then specifies the name
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of this datasource, which encompasses details such as the specific ODBC driver
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in use as well as the network address of the database. Assuming a datasource
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is configured on the client, a basic DSN-based connection looks like::
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engine = create_engine("mssql+pyodbc://scott:tiger@some_dsn")
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Which above, will pass the following connection string to PyODBC::
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DSN=some_dsn;UID=scott;PWD=tiger
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If the username and password are omitted, the DSN form will also add
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the ``Trusted_Connection=yes`` directive to the ODBC string.
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Hostname Connections
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^^^^^^^^^^^^^^^^^^^^
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Hostname-based connections are also supported by pyodbc. These are often
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easier to use than a DSN and have the additional advantage that the specific
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database name to connect towards may be specified locally in the URL, rather
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than it being fixed as part of a datasource configuration.
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When using a hostname connection, the driver name must also be specified in the
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query parameters of the URL. As these names usually have spaces in them, the
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name must be URL encoded which means using plus signs for spaces::
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engine = create_engine("mssql+pyodbc://scott:tiger@myhost:port/databasename?driver=ODBC+Driver+17+for+SQL+Server")
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The ``driver`` keyword is significant to the pyodbc dialect and must be
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specified in lowercase.
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Any other names passed in the query string are passed through in the pyodbc
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connect string, such as ``authentication``, ``TrustServerCertificate``, etc.
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Multiple keyword arguments must be separated by an ampersand (``&``); these
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will be translated to semicolons when the pyodbc connect string is generated
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internally::
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e = create_engine(
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"mssql+pyodbc://scott:tiger@mssql2017:1433/test?"
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"driver=ODBC+Driver+18+for+SQL+Server&TrustServerCertificate=yes"
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"&authentication=ActiveDirectoryIntegrated"
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)
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The equivalent URL can be constructed using :class:`_sa.engine.URL`::
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from sqlalchemy.engine import URL
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connection_url = URL.create(
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"mssql+pyodbc",
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username="scott",
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password="tiger",
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host="mssql2017",
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port=1433,
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database="test",
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query={
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"driver": "ODBC Driver 18 for SQL Server",
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"TrustServerCertificate": "yes",
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"authentication": "ActiveDirectoryIntegrated",
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},
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)
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Pass through exact Pyodbc string
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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A PyODBC connection string can also be sent in pyodbc's format directly, as
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specified in `the PyODBC documentation
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<https://github.com/mkleehammer/pyodbc/wiki/Connecting-to-databases>`_,
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using the parameter ``odbc_connect``. A :class:`_sa.engine.URL` object
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can help make this easier::
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from sqlalchemy.engine import URL
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connection_string = "DRIVER={SQL Server Native Client 10.0};SERVER=dagger;DATABASE=test;UID=user;PWD=password"
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connection_url = URL.create("mssql+pyodbc", query={"odbc_connect": connection_string})
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engine = create_engine(connection_url)
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.. _mssql_pyodbc_access_tokens:
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Connecting to databases with access tokens
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Some database servers are set up to only accept access tokens for login. For
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example, SQL Server allows the use of Azure Active Directory tokens to connect
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to databases. This requires creating a credential object using the
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``azure-identity`` library. More information about the authentication step can be
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found in `Microsoft's documentation
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<https://docs.microsoft.com/en-us/azure/developer/python/azure-sdk-authenticate?tabs=bash>`_.
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After getting an engine, the credentials need to be sent to ``pyodbc.connect``
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each time a connection is requested. One way to do this is to set up an event
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listener on the engine that adds the credential token to the dialect's connect
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call. This is discussed more generally in :ref:`engines_dynamic_tokens`. For
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SQL Server in particular, this is passed as an ODBC connection attribute with
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a data structure `described by Microsoft
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<https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_.
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The following code snippet will create an engine that connects to an Azure SQL
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database using Azure credentials::
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import struct
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from sqlalchemy import create_engine, event
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from sqlalchemy.engine.url import URL
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from azure import identity
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SQL_COPT_SS_ACCESS_TOKEN = 1256 # Connection option for access tokens, as defined in msodbcsql.h
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TOKEN_URL = "https://database.windows.net/" # The token URL for any Azure SQL database
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connection_string = "mssql+pyodbc://@my-server.database.windows.net/myDb?driver=ODBC+Driver+17+for+SQL+Server"
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engine = create_engine(connection_string)
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azure_credentials = identity.DefaultAzureCredential()
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@event.listens_for(engine, "do_connect")
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def provide_token(dialect, conn_rec, cargs, cparams):
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# remove the "Trusted_Connection" parameter that SQLAlchemy adds
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cargs[0] = cargs[0].replace(";Trusted_Connection=Yes", "")
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# create token credential
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raw_token = azure_credentials.get_token(TOKEN_URL).token.encode("utf-16-le")
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token_struct = struct.pack(f"<I{len(raw_token)}s", len(raw_token), raw_token)
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# apply it to keyword arguments
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cparams["attrs_before"] = {SQL_COPT_SS_ACCESS_TOKEN: token_struct}
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.. tip::
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The ``Trusted_Connection`` token is currently added by the SQLAlchemy
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pyodbc dialect when no username or password is present. This needs
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to be removed per Microsoft's
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`documentation for Azure access tokens
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<https://docs.microsoft.com/en-us/sql/connect/odbc/using-azure-active-directory#authenticating-with-an-access-token>`_,
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stating that a connection string when using an access token must not contain
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``UID``, ``PWD``, ``Authentication`` or ``Trusted_Connection`` parameters.
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.. _azure_synapse_ignore_no_transaction_on_rollback:
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Avoiding transaction-related exceptions on Azure Synapse Analytics
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Azure Synapse Analytics has a significant difference in its transaction
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handling compared to plain SQL Server; in some cases an error within a Synapse
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transaction can cause it to be arbitrarily terminated on the server side, which
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then causes the DBAPI ``.rollback()`` method (as well as ``.commit()``) to
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fail. The issue prevents the usual DBAPI contract of allowing ``.rollback()``
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to pass silently if no transaction is present as the driver does not expect
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this condition. The symptom of this failure is an exception with a message
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resembling 'No corresponding transaction found. (111214)' when attempting to
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emit a ``.rollback()`` after an operation had a failure of some kind.
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This specific case can be handled by passing ``ignore_no_transaction_on_rollback=True`` to
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the SQL Server dialect via the :func:`_sa.create_engine` function as follows::
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engine = create_engine(connection_url, ignore_no_transaction_on_rollback=True)
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Using the above parameter, the dialect will catch ``ProgrammingError``
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exceptions raised during ``connection.rollback()`` and emit a warning
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if the error message contains code ``111214``, however will not raise
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an exception.
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.. versionadded:: 1.4.40 Added the
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``ignore_no_transaction_on_rollback=True`` parameter.
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Enable autocommit for Azure SQL Data Warehouse (DW) connections
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Azure SQL Data Warehouse does not support transactions,
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and that can cause problems with SQLAlchemy's "autobegin" (and implicit
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commit/rollback) behavior. We can avoid these problems by enabling autocommit
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at both the pyodbc and engine levels::
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connection_url = sa.engine.URL.create(
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"mssql+pyodbc",
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username="scott",
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password="tiger",
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host="dw.azure.example.com",
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database="mydb",
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query={
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"driver": "ODBC Driver 17 for SQL Server",
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"autocommit": "True",
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},
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)
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engine = create_engine(connection_url).execution_options(
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isolation_level="AUTOCOMMIT"
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)
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Avoiding sending large string parameters as TEXT/NTEXT
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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By default, for historical reasons, Microsoft's ODBC drivers for SQL Server
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send long string parameters (greater than 4000 SBCS characters or 2000 Unicode
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characters) as TEXT/NTEXT values. TEXT and NTEXT have been deprecated for many
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years and are starting to cause compatibility issues with newer versions of
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SQL_Server/Azure. For example, see `this
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issue <https://github.com/mkleehammer/pyodbc/issues/835>`_.
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Starting with ODBC Driver 18 for SQL Server we can override the legacy
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behavior and pass long strings as varchar(max)/nvarchar(max) using the
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``LongAsMax=Yes`` connection string parameter::
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connection_url = sa.engine.URL.create(
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"mssql+pyodbc",
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username="scott",
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password="tiger",
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host="mssqlserver.example.com",
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database="mydb",
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query={
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"driver": "ODBC Driver 18 for SQL Server",
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"LongAsMax": "Yes",
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},
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)
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Pyodbc Pooling / connection close behavior
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------------------------------------------
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PyODBC uses internal `pooling
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<https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ by
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default, which means connections will be longer lived than they are within
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SQLAlchemy itself. As SQLAlchemy has its own pooling behavior, it is often
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preferable to disable this behavior. This behavior can only be disabled
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globally at the PyODBC module level, **before** any connections are made::
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import pyodbc
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pyodbc.pooling = False
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# don't use the engine before pooling is set to False
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engine = create_engine("mssql+pyodbc://user:pass@dsn")
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If this variable is left at its default value of ``True``, **the application
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will continue to maintain active database connections**, even when the
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SQLAlchemy engine itself fully discards a connection or if the engine is
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disposed.
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.. seealso::
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`pooling <https://github.com/mkleehammer/pyodbc/wiki/The-pyodbc-Module#pooling>`_ -
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in the PyODBC documentation.
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Driver / Unicode Support
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-------------------------
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PyODBC works best with Microsoft ODBC drivers, particularly in the area
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of Unicode support on both Python 2 and Python 3.
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Using the FreeTDS ODBC drivers on Linux or OSX with PyODBC is **not**
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recommended; there have been historically many Unicode-related issues
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in this area, including before Microsoft offered ODBC drivers for Linux
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and OSX. Now that Microsoft offers drivers for all platforms, for
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PyODBC support these are recommended. FreeTDS remains relevant for
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non-ODBC drivers such as pymssql where it works very well.
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Rowcount Support
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----------------
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Previous limitations with the SQLAlchemy ORM's "versioned rows" feature with
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Pyodbc have been resolved as of SQLAlchemy 2.0.5. See the notes at
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:ref:`mssql_rowcount_versioning`.
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.. _mssql_pyodbc_fastexecutemany:
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Fast Executemany Mode
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---------------------
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.. note:: SQLAlchemy 2.0 now includes an equivalent "fast executemany"
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handler for INSERT statements that is more robust than the PyODBC feature;
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the feature is called :ref:`insertmanyvalues <engine_insertmanyvalues>`
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and is enabled by default for all INSERT statements used by SQL Server.
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SQLAlchemy's feature integrates with the PyODBC ``setinputsizes()`` method
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which allows for more accurate specification of datatypes, and additionally
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uses a dynamically sized, batched approach that scales to any number of
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columns and/or rows.
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The SQL Server ``fast_executemany`` parameter may be used at the same time
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as ``insertmanyvalues`` is enabled; however, the parameter will not be used
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in as many cases as INSERT statements that are invoked using Core
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:class:`_dml.Insert` constructs as well as all ORM use no longer use the
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``.executemany()`` DBAPI cursor method.
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The PyODBC driver includes support for a "fast executemany" mode of execution
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which greatly reduces round trips for a DBAPI ``executemany()`` call when using
|
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Microsoft ODBC drivers, for **limited size batches that fit in memory**. The
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feature is enabled by setting the attribute ``.fast_executemany`` on the DBAPI
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cursor when an executemany call is to be used. The SQLAlchemy PyODBC SQL
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Server dialect supports this parameter by passing the
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``fast_executemany`` parameter to
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:func:`_sa.create_engine` , when using the **Microsoft ODBC driver only**::
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engine = create_engine(
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"mssql+pyodbc://scott:tiger@mssql2017:1433/test?driver=ODBC+Driver+17+for+SQL+Server",
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fast_executemany=True)
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|
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.. versionadded:: 1.3
|
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|
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.. seealso::
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|
|
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|
`fast executemany <https://github.com/mkleehammer/pyodbc/wiki/Features-beyond-the-DB-API#fast_executemany>`_
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- on github
|
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|
|
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|
.. _mssql_pyodbc_setinputsizes:
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|
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|
Setinputsizes Support
|
||
|
-----------------------
|
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|
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As of version 2.0, the pyodbc ``cursor.setinputsizes()`` method is used for
|
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all statement executions, except for ``cursor.executemany()`` calls when
|
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fast_executemany=True where it is not supported (assuming
|
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|
: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
|
||
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be turned off by passing ``use_setinputsizes=False`` to
|
||
|
:func:`_sa.create_engine`.
|
||
|
|
||
|
""" # noqa
|
||
|
|
||
|
|
||
|
import datetime
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||
|
import decimal
|
||
|
import re
|
||
|
import struct
|
||
|
|
||
|
from .base import _MSDateTime
|
||
|
from .base import _MSUnicode
|
||
|
from .base import _MSUnicodeText
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||
|
from .base import BINARY
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||
|
from .base import DATETIMEOFFSET
|
||
|
from .base import MSDialect
|
||
|
from .base import MSExecutionContext
|
||
|
from .base import VARBINARY
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||
|
from .json import JSON as _MSJson
|
||
|
from .json import JSONIndexType as _MSJsonIndexType
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||
|
from .json import JSONPathType as _MSJsonPathType
|
||
|
from ... import exc
|
||
|
from ... import types as sqltypes
|
||
|
from ... import util
|
||
|
from ...connectors.pyodbc import PyODBCConnector
|
||
|
|
||
|
|
||
|
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)
|
||
|
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().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
|
||
|
|
||
|
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
|