python cx oracle expecting string, unicode or buffer object

Question

I am trying to run following code snippet in python to connect to oracle, but constantly running into following error. I have tried a lot of combinations but it doesn't seem to work. I understand the error, but don't understand what is incompatible here. Has anyone come across this issue? How do I fix it?

File "", line 1, in File "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1613, in execute

connection = self.contextual_connect(close_with_result=True)   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1661, in contextual_connect  

self.pool.connect(),   File "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 326, in connect  

return _ConnectionFairy(self).checkout()   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 485, in __init__  

rec = self._connection_record = pool._do_get()   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 770, in _do_get  

return self._create_connection()   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 279, in _create_connection  

return _ConnectionRecord(self)   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 372, in __init__   

self.connection = self.__connect()   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/pool.py", line 433, in __connect  

connection = self.__pool._creator()   File    "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/engine/strategies.py", line 80, in connect

return dialect.connect(*cargs, **cparams)   File   "/workplace/applications/python2.7/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 283, in connect

return self.dbapi.connect(*cargs, **cparams)    

TypeError: expecting string, unicode or buffer object


from sqlalchemy.ext.declarative import declarative_base;
from sqlalchemy import create_engine;
engine = create_engine(u'oracle+cx_oracle://localhost:1521/orcl', echo=True)
result = engine.execute(u"select 1 from dual");

Setup:

Python 2.7
SqlAlchemy 0.9.7 and 0.8.7
Cx Oracle (latest version)
Oracle Database 10g Release 10.2.0.2.0

Answer 1

If you are running into this problem, most likely the cause is that you are not passing in arguments required by the underlying dbapi call.

In my case I added additional arguments of user, password and dsn to the create_engine call along with existing ones, which got passed to cx_oracle call and it worked.

something like this should work

create_engine(u'oracle+cx_oracle://localhost:1521/orcl', echo=True, user='<>', password='<>', dsn='<>')