# pysybase.py
# Copyright (C) 2010 Michael Bayer mike_mp@zzzcomputing.com
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
Support for Sybase via the python-sybase driver.
http://python-sybase.sourceforge.net/
Connect strings are of the form::
sybase+pysybase://<username>:<password>@<dsn>/[database name]
Unicode Support
---------------
The python-sybase driver does not appear to support non-ASCII strings of any
kind at this time.
"""
from sqlalchemy import types
from sqlalchemy.dialects.sybase.base import SybaseDialect,\
SybaseExecutionContext, SybaseSQLCompiler
class _SybNumeric(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 SybaseExecutionContext_pysybase(SybaseExecutionContext):
def set_ddl_autocommit(self, dbapi_connection, value):
if value:
# call commit() on the Sybase connection directly,
# to avoid any side effects of calling a Connection
# transactional method inside of pre_exec()
dbapi_connection.commit()
def pre_exec(self):
SybaseExecutionContext.pre_exec(self)
for param in self.parameters:
for key in list(param):
param["@" + key] = param[key]
del param[key]
class SybaseSQLCompiler_pysybase(SybaseSQLCompiler):
def bindparam_string(self, name):
return "@" + name
class SybaseDialect_pysybase(SybaseDialect):
driver = 'pysybase'
execution_ctx_cls = SybaseExecutionContext_pysybase
statement_compiler = SybaseSQLCompiler_pysybase
colspecs={
sqltypes.Numeric:_SybNumeric,
sqltypes.Float:sqltypes.Float
}
@classmethod
def dbapi(cls):
import Sybase
return Sybase
def create_connect_args(self, url):
opts = url.translate_connect_args(username='user', password='passwd')
return ([opts.pop('host')], opts)
def do_executemany(self, cursor, statement, parameters, context=None):
# calling python-sybase executemany yields:
# TypeError: string too long for buffer
for param in parameters:
cursor.execute(statement, param)
def _get_server_version_info(self, connection):
vers = connection.scalar("select @@version_number")
# i.e. 15500, 15000, 12500 == (15, 5, 0, 0), (15, 0, 0, 0), (12, 5, 0, 0)
return (vers / 1000, vers % 1000 / 100, vers % 100 / 10, vers % 10)
def is_disconnect(self, e):
if isinstance(e, (self.dbapi.OperationalError, self.dbapi.ProgrammingError)):
msg = str(e)
return ('Unable to complete network request to host' in msg or
'Invalid connection state' in msg or
'Invalid cursor state' in msg)
else:
return False
dialect = SybaseDialect_pysybase
|