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import sys
import _mssql
import pymssql as dbapi2
from pymssql import OperationalError, pymssqlCursor as Cursor
ISOLATION_LEVELS = (
None, 'READ UNCOMMITTED', 'READ COMMITTED', 'REPEATABLE READ',
'SERIALIZABLE')
placeholder = '%s'
## notice that retrieving the internal size does not work with pymssql
CODEMAP = {
1: 'VARCHAR',
2: 'INTEGER',
3: 'FLOAT',
4: 'DATETIME',
}
class Connection(object):
def __init__(self, cnx, isolation_level=None):
assert isolation_level in ISOLATION_LEVELS, isolation_level
self._cnx = cnx
self.isolation_level = isolation_level
if isolation_level:
cnx.query("set transaction isolation level " + isolation_level)
try:
self._cnx.query("begin tran")
self._cnx.fetch_array()
except Exception, e:
raise OperationalError(e)
def cursor(self):
if self._cnx is None:
raise OperationalError("Closed connection")
cursor = Cursor(self._cnx)
if not hasattr(cursor, 'connection'): # for old versions of pymssql
cursor.connection = self
return cursor
def close(self):
if self._cnx is None:
return # the connection was already closed
self._cnx.close()
self._cnx = None
def commit(self):
if self._cnx is None:
raise OperationalError("Closed connection")
try:
self._cnx.query("commit tran")
self._cnx.fetch_array()
self._cnx.query("begin tran")
self._cnx.fetch_array()
except Exception, e:
raise OperationalError, "can't commit: %s" % e, sys.exc_info()[2]
def rollback(self):
if self._cnx is None:
raise OperationalError("Closed connection")
try:
self._cnx.query("rollback tran")
self._cnx.fetch_array()
self._cnx.query("begin tran")
self._cnx.fetch_array()
except Exception, e:
# XXX: sometimes the can't rollback message is wrong; a typical
# example is to try to create an already existing table with
# try: <create> except: <rollback>; SQL server performs an
# inner rollback, so that you should not call the second one
# the error here can be declassed to a Warning
raise OperationalError, "can't rollback: %s" % e, sys.exc_info()[2]
def connect(params, isolation_level=None):
user, pwd, host, port, db = params
port = port or 1433
if sys.platform != 'win32': # on linux
if '\\' in host: # strip the instance
host, instance = host.split('\\')
host = '%s:%s' % (host, port) # add the port
_conn = _mssql.connect(host, user, pwd)
_conn.select_db(db)
return Connection(_conn, isolation_level)
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