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- # mysql/pyodbc.py
- # Copyright (C) 2005-2022 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
- r"""
- .. dialect:: mysql+pyodbc
- :name: PyODBC
- :dbapi: pyodbc
- :connectstring: mysql+pyodbc://<username>:<password>@<dsnname>
- :url: https://pypi.org/project/pyodbc/
- .. note::
- The PyODBC for MySQL dialect is **not tested as part of
- SQLAlchemy's continuous integration**.
- The recommended MySQL dialects are mysqlclient and PyMySQL.
- However, if you want to use the mysql+pyodbc dialect and require
- full support for ``utf8mb4`` characters (including supplementary
- characters like emoji) be sure to use a current release of
- MySQL Connector/ODBC and specify the "ANSI" (**not** "Unicode")
- version of the driver in your DSN or connection string.
- Pass through exact pyodbc connection string::
- import urllib
- connection_string = (
- 'DRIVER=MySQL ODBC 8.0 ANSI Driver;'
- 'SERVER=localhost;'
- 'PORT=3307;'
- 'DATABASE=mydb;'
- 'UID=root;'
- 'PWD=(whatever);'
- 'charset=utf8mb4;'
- )
- params = urllib.parse.quote_plus(connection_string)
- connection_uri = "mysql+pyodbc:///?odbc_connect=%s" % params
- """ # noqa
- import re
- from .base import MySQLDialect
- from .base import MySQLExecutionContext
- from .types import TIME
- from ... import exc
- from ... import util
- from ...connectors.pyodbc import PyODBCConnector
- from ...sql.sqltypes import Time
- class _pyodbcTIME(TIME):
- def result_processor(self, dialect, coltype):
- def process(value):
- # pyodbc returns a datetime.time object; no need to convert
- return value
- return process
- class MySQLExecutionContext_pyodbc(MySQLExecutionContext):
- def get_lastrowid(self):
- cursor = self.create_cursor()
- cursor.execute("SELECT LAST_INSERT_ID()")
- lastrowid = cursor.fetchone()[0]
- cursor.close()
- return lastrowid
- class MySQLDialect_pyodbc(PyODBCConnector, MySQLDialect):
- supports_statement_cache = True
- colspecs = util.update_copy(MySQLDialect.colspecs, {Time: _pyodbcTIME})
- supports_unicode_statements = True
- execution_ctx_cls = MySQLExecutionContext_pyodbc
- pyodbc_driver_name = "MySQL"
- def _detect_charset(self, connection):
- """Sniff out the character set in use for connection results."""
- # Prefer 'character_set_results' for the current connection over the
- # value in the driver. SET NAMES or individual variable SETs will
- # change the charset without updating the driver's view of the world.
- #
- # If it's decided that issuing that sort of SQL leaves you SOL, then
- # this can prefer the driver value.
- try:
- value = connection.exec_driver_sql(
- "select @@character_set_client"
- ).scalar()
- if value:
- return value
- except exc.DBAPIError:
- pass
- util.warn(
- "Could not detect the connection character set. "
- "Assuming latin1."
- )
- return "latin1"
- def _extract_error_code(self, exception):
- m = re.compile(r"\((\d+)\)").search(str(exception.args))
- c = m.group(1)
- if c:
- return int(c)
- else:
- return None
- def on_connect(self):
- super_ = super(MySQLDialect_pyodbc, self).on_connect()
- def on_connect(conn):
- if super_ is not None:
- super_(conn)
- # declare Unicode encoding for pyodbc as per
- # https://github.com/mkleehammer/pyodbc/wiki/Unicode
- pyodbc_SQL_CHAR = 1 # pyodbc.SQL_CHAR
- pyodbc_SQL_WCHAR = -8 # pyodbc.SQL_WCHAR
- conn.setdecoding(pyodbc_SQL_CHAR, encoding="utf-8")
- conn.setdecoding(pyodbc_SQL_WCHAR, encoding="utf-8")
- conn.setencoding(encoding="utf-8")
- return on_connect
- dialect = MySQLDialect_pyodbc
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