Python 2.7.3 (default, Jan 4 2013, 14:06:23)
[GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] on
darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlalchemy
>>> print sqlalchemy.__version__
0.8.0b2
Below is the code I was able to use to reproduce a problem I was having.
Here is the stack trace:
Traceback (most recent call last):
File "test.py", line 48, in <module>
print session.query(AbstractConcreteAbstraction).all()
File "/usr/local/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
line 1079, in query
return self._query_cls(entities, self, **kwargs)
File "/usr/local/lib/python2.7/site-packages/sqlalchemy/orm/query.py",
line 115, in __init__
self._set_entities(entities)
File "/usr/local/lib/python2.7/site-packages/sqlalchemy/orm/query.py",
line 122, in _set_entities
entity_wrapper(self, ent)
File "/usr/local/lib/python2.7/site-packages/sqlalchemy/orm/query.py",
line 2949, in __init__
"expected - got '%r'" % (column, )
sqlalchemy.exc.InvalidRequestError: SQL expression, column, or mapped
entity expected - got '<class '__main__.AbstractConcreteAbstraction'>'
The workaround I discovered while trying to reproduce is to simply
instantiate a subclass... am I missing something?
from sqlalchemy.engine import Engine
from sqlalchemy import event
from sqlalchemy import (Column, Integer, Unicode, DateTime, ForeignKey,
Boolean, Numeric, Time)
# Taken from http://docs.sqlalchemy.org/ru/latest/dialects/sqlite.html
@event.listens_for(Engine, "connect")
def set_sqlite_pragma(dbapi_connection, connection_record):
cursor = dbapi_connection.cursor()
cursor.execute("PRAGMA foreign_keys=ON")
cursor.close()
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import (declarative_base, declared_attr,
AbstractConcreteBase)
from sqlalchemy.orm import sessionmaker
engine = create_engine('sqlite:///test.db')
sqlite = declarative_base(bind=engine)
get_session = sessionmaker(bind=engine)
session = get_session()
from sqlalchemy.schema import UniqueConstraint
class AbstractConcreteAbstraction(AbstractConcreteBase, sqlite):
__table_args__ = (UniqueConstraint('derpa',
'derp'),)
id = Column(Integer, primary_key=True)
derpa = Column(Integer)
derp = Column(Integer)
class ConcreteConcreteAbstraction(AbstractConcreteAbstraction):
__tablename__ = u'cca'
__mapper_args__ = {'polymorphic_identity': 'ccb',
'concrete': True}
print AbstractConcreteAbstraction
sqlite.metadata.create_all()
# DOES NOT WORK WITHOUT!!!
# ConcreteConcreteAbstraction(derpa=2, derp=2)
print session.query(AbstractConcreteAbstraction).all()
print session.query(ConcreteConcreteAbstraction).all()
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