"""Support for the MySQL database via the pyodbc adapter.
pyodbc is available at:
http://pypi.python.org/pypi/pyodbc/
Connecting
----------
Connect string::
mysql+pyodbc://<username>:<password>@<dsnname>
Limitations
-----------
The mysql-pyodbc dialect is subject to unresolved character encoding issues
which exist within the current ODBC drivers available.
(see http://code.google.com/p/pyodbc/issues/detail?id=25). Consider usage
of OurSQL, MySQLdb, or MySQL-connector/Python.
"""
from sqlalchemy.dialects.mysql.base import MySQLDialect,MySQLExecutionContext
from sqlalchemy.connectors.pyodbc import PyODBCConnector
from sqlalchemy.engine import base
from sqlalchemy import util
import re
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_unicode_statements = False
execution_ctx_cls = MySQLExecutionContext_pyodbc
pyodbc_driver_name = "MySQL"
def __init__(self, **kw):
# deal with http://code.google.com/p/pyodbc/issues/detail?id=25
kw.setdefault('convert_unicode', True)
super(MySQLDialect_pyodbc, self).__init__(**kw)
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.
rs = connection.execute("SHOW VARIABLES LIKE 'character_set%%'")
opts = dict([(row[0], row[1]) for row in self._compat_fetchall(rs)])
for key in ('character_set_connection', 'character_set'):
if opts.get(key, None):
return opts[key]
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.orig.args))
c = m.group(1)
if c:
return int(c)
else:
return None
dialect = MySQLDialect_pyodbc
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