SQLAlchemy - get() can only be used against a single mapped class - sqlalchemy

Question

Noob to SQLAlchemy. :/
Using Python 2.7 with SQLAlchemy 0.9.2 on Windows 7.
I receive the message
Traceback (most recent call last):
File "test.py", line 46, in <module>
result = Session().query(Table_Enum_country).get(1)
File "c:\Python27\lib\site-packages\sqlalchemy-0.9.2-py2.7.egg\sqlalchemy\orm\query.py", line 786, in get
mapper = self._only_full_mapper_zero("get")
File "c:\Python27\lib\site-packages\sqlalchemy-0.9.2-py2.7.egg\sqlalchemy\orm\query.py", line 322, in _only_full_mapper_zero
"a single mapped class." % methname)
sqlalchemy.exc.InvalidRequestError: get() can only be used against a single mapped class.
I have a SQL Server 2012 table defined as follows :-
CREATE TABLE [dbo].[enum_countries](
[created_at] [datetime] NULL,
[updated_at] [datetime] NULL,
[updated_by_id] [int] NULL,
[created_by_id] [int] NULL,
[name] [nvarchar](256) NULL,
[description] [nvarchar](256) NULL,
[_enabled] [bit] NULL,
[nationality] [nvarchar](50) NULL,
[id] [int] IDENTITY(1,1) NOT NULL,
[code] [nvarchar](10) NULL,
CONSTRAINT [PK__enum_countries__4CA06362] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]
My Python code is as follows :-
import logging
logging.basicConfig(level=logging.DEBUG)
logging.getLogger("sqlalchemy").setLevel(logging.WARN)
from sqlalchemy import create_engine
from sqlalchemy import MetaData
from sqlalchemy import Table
from sqlalchemy.orm import sessionmaker
# Initialize SQLAlchemy Environment
db = create_engine(
"mssql://user:password#localhost/localDB")
Session = sessionmaker(bind=db)
metadata = MetaData()
# Grab ALL tables in one hit.
# metadata.reflect(bind=db)
Table_Enum_country = Table(u'enum_countries', metadata, autoload=True, autoload_with=db)
result = Session().query(Table_Enum_country).get(1)
print result
What am I doing wrong? Why can't I simply 'get()' the row?
If there is a better way of doing this, I am all eyes :)
Thanks in advance.
...Lyall

Answer 1

Session.get() is for mapped classes, not for sql entities, for that you should use Table.select().
session.execute(Table_Enum_country.select().where( Table_Enum_country.columns.id == 1))
alternatively, map the table to a class:
from sqlalchemy.orm import mapper
class EnumContries(object):
pass
mapper(EnumContries, Table_Enum_country)
instance = session.query(EnumContries).get(1)