Michael,
thanks for clearing it up for me.
I've modified the code to use
objectstore.query(User).get(1)
and it worked.
So (correct me if I'm wrong) the Query objects
should be created in the same thread where
they going to be used?
Regards,
Anton
--- Michael Bayer <[EMAIL PROTECTED]> wrote:
> > user = self.user_query.get(1)
> > Message(origin=user.node, text='abcd')
>
>
> > InvalidRequestError: Object
> '<culture.model.Message
> > object at 0x4765490c>' is already attached to
> session
> > '1197808844' (this is '1082348588')
>
> When you create Message, it is automatically
> associated with the
> current thread's session (as a result of the
> threadlocal mod). When
> you then attach the "user.node" object to its
> "origin" property, the
> Message mapper wants to "cascade" its session
> association to its
> child objects, which then produces an error since
> "user.node" is
> already associated with some other session,
> presumably because it was
> loaded in some other thread since the Query that
> loaded it is an
> instance variable.
>
> this cascading behavior can be configured to behave
> differently, but
> its likely that you would want connected objects to
> all be within the
> same session.
>
> so when you query for the user object, that query
> should most likely
> be done in the context of the current thread's
> session, which when
> using the "threadlocal" mod as you are doing is
> accessed via the
> "objectstore" object:
>
> user = objectstore.query(User).get(1)
> Message(origin=user.node, text='abcd')
>
>
> On May 31, 2006, at 7:21 AM, Anton Krasovsky wrote:
>
> > Hi,
> >
> > I'm using SQLAlchemy 0.2.1 with Turbogears,
> > and I see an error when trying to create an
> instance
> > of a mapped object.
> >
> > Environment is as follows:
> >
> > sqlalchemy is imported with:
> >
> > import sqlalchemy.mods.threadlocal
> > import sqlalchemy
> >
> > module 'model' defines number of Table's objects
> and
> > their mappings, in particular:
> >
> > node_table = Table( "node", __engine__,
> > Column( 'node_id', Integer, primary_key=True
> ),
> > )
> >
> > message_table = Table( "message", __engine__,
> > Column( 'message_id', Integer,
> primary_key=True ),
> > Column('text', String(255), nullable=False),
> > Column('node_id', Integer,
> > ForeignKey('node.node_id')),
> > Column('created', DateTime),
> > )
> >
> > class Node(object):
> > pass
> >
> > class User(object):
> > def __init__(self, node, email, password):
> > self.email = email
> > self.password = password
> > self.node = node
> >
> > class Message(object):
> > def __init__(self, origin, text,
> > created=datetime.now()):
> > self.origin = origin
> > self.text = text
> > self.created = created
> >
> > mapper(Node, node_table)
> >
> > mapper(User, user_table, properties = {
> > 'node' : relation(Node)
> > }
> > )
> >
> > mapper(Message, message_table, properties = {
> > 'origin' : relation(Node, backref='messages')
> > }
> > )
> >
> > When turbogears starts, it imports this module
> (and
> > presumably also starts several threads)
> >
> > I'm trying to create instance of Message from
> within
> > of one thread, with:
> >
> > user = self.user_query.get(1)
> > Message(origin=user.node, text='abcd')
> >
> > And I get following exception:
> >
> > ......
> > File
> "/home/anton/culture/culture/controllers.py",
> > line 91, in submit
> > Message(origin=user.node, text=body)
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/mapper.py",
> > line 398, in init
> > File "/home/anton/culture/culture/model.py",
> line
> > 70, in __init__
> > self.origin = origin
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 56, in __set__
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 373, in set_attribute
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 140, in setattr
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 322, in set
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/unitofwork.py",
> > line 57, in append
> > File
> > "build/bdist.linux-i686/egg/sqlalchemy/util.py",
> line
> > 387, in append
> > File
> > "build/bdist.linux-i686/egg/sqlalchemy/util.py",
> line
> > 295, in __setrecord
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 217, in do_value_appended
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/attributes.py",
> > line 92, in value_changed
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/unitofwork.py",
> > line 52, in do_value_changed
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/session.py",
> > line 300, in save_or_update
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/session.py",
> > line 339, in _save_impl
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/session.py",
> > line 357, in _register_new
> > File
> >
>
"build/bdist.linux-i686/egg/sqlalchemy/orm/session.py",
> > line 374, in _attach
> > InvalidRequestError: Object
> '<culture.model.Message
> > object at 0x4765490c>' is already attached to
> session
> > '1197808844' (this is '1082348588')
> >
> > However I'm able to create instance of Message in
> > similar way, when not using threads.
> >
> > Please advise if I'm doing something wrong here,
> > as I'm new to SQLAlchemy.
> >
> > Regards,
>
=== message truncated ===
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