librelist archives

Re: [flask] Question about flask-sqlalchemy updating existing records.

From:

Andrey V. Martyanov

Date:

2011-12-05 @ 11:45

You are right, Adam! My mistake.

On Mon, Dec 5, 2011 at 4:30 PM, Adam Patterson <fakeempire@gmail.com> wrote:

> This is a quote from Armin:
> "Unnecessary for modifications. The object is automatically part of
> the session if it was retrieved via Object.query."
>
> Here is the context:
>
> 
http://flask.pocoo.org/mailinglist/archive/2011/10/18/updating-an-existing-record-with-sqlalchemy/
>
> You can see Armin's response about 5 messages down.
>
>
> On Mon, Dec 5, 2011 at 6:16 PM, Andrey V. Martyanov <realduke@gmail.com>
> wrote:
> > Adam, added by whom? You should explicitly add an object to the session.
> >
> >
> >> On Mon, Dec 5, 2011 at 11:45 AM, Adam Patterson <fakeempire@gmail.com>
> >> wrote:
> >>>
> >>> Correct me if I'm wrong but I don't think you need to add user to the
> >>> session when you are modifying existing records. I believe its already
> >>> added.
> >>>
> >>> On Mon, Dec 5, 2011 at 11:05 AM, Thomas Dziedzic <gostrc@gmail.com>
> >>> wrote:
> >>> > Ah, that works,
> >>> > but I'm still left a little confused, maybe you can explain this or
> >>> > point me to some resources that would explain this;
> >>> >
> >>> > in my app.py I have something like:
> >>> > ...
> >>> > db = SQLAlchemy(app)
> >>> > import models
> >>> > user = User.query.filter_by(email='tom@google.com').first()
> >>> > user.viewpassword = 'hi'
> >>> > db.session.add(user)
> >>> >
> >>> > and this doesn't work,
> >>> >
> >>> > but if I import db from models, it seems to work,
> >>> > so it looks like db is different in app.py and models.py
> >>> > I'm confused as how this works and how I could use the right db in
> >>> > app.py so that something like db.session.add(user) would work in
> >>> > app.py and not just an external file.
> >>> >
> >>> > basically I want to have the controller portion in app.py and the
> >>> > models seperated into models.py. Is there a clean way of doing this?
> >>> >
> >>> > Thanks for your time and answers.
> >>> >
> >>> > On Sun, Dec 4, 2011 at 7:59 PM, Andrey V. Martyanov
> >>> > <realduke@gmail.com> wrote:
> >>> >> For your specific situation the following should work:
> >>> >>
> >>> >> app.py
> >>> >>
> >>> >> from flask import Flask
> >>> >> app = Flask(__name__)
> >>> >> app.config['SQLALCHEMY_DATABASE_URI'] =
> >>> >> 'mysql://root:tom123@localhost/idabble'
> >>> >> from flaskext.sqlalchemy import SQLAlchemy
> >>> >> db = SQLAlchemy(app)
> >>> >>
> >>> >> model.py
> >>> >>
> >>> >> from app import db
> >>> >>
> >>> >> class User(db.Model):
> >>> >>     # Provide your model definition
> >>> >>     pass
> >>> >>
> >>> >>>>> from model import db, User
> >>> >>>>> user = User.query.filter_by(email='tom@google.com').first()
> >>> >>>>> user.viewpassword = 'hi'
> >>> >>>>> db.session.add(user)
> >>> >>>>> db.session.commit()
> >>> >>
> >>> >> On Mon, Dec 5, 2011 at 6:44 AM, Andrey V. Martyanov
> >>> >> <realduke@gmail.com>
> >>> >> wrote:
> >>> >>>
> >>> >>> It's unclear to me what your model contains. If you want to
> separate
> >>> >>> the
> >>> >>> main application initialization from models then you need  to
> >>> >>> explicitly
> >>> >>> import SQLAlchemy instance and use it's Model class as a base class
> >>> >>> for all
> >>> >>> your models.
> >>> >>>
> >>> >>> Example, based on your code:
> >>> >>>
> >>> >>> app.py
> >>> >>>
> >>> >>> from flask import Flask
> >>> >>> app = Flask(__name__)
> >>> >>> app.config['SQLALCHEMY_DATABASE_URI'] =
> >>> >>> 'mysql://root:tom123@localhost/idabble'
> >>> >>> from flaskext.sqlalchemy import SQLAlchemy
> >>> >>> db = SQLAlchemy(app)
> >>> >>>
> >>> >>> model.py
> >>> >>>
> >>> >>> from .app import db
> >>> >>>
> >>> >>> class User(db.Model):
> >>> >>>     pass
> >>> >>>
> >>> >>> On Mon, Dec 5, 2011 at 4:55 AM, Thomas Dziedzic <gostrc@gmail.com>
> >>> >>> wrote:
> >>> >>>>
> >>> >>>> Hi, thanks for the suggestion, but it didn't work:
> >>> >>>>
> >>> >>>> I put this right before db.session.commit() and got the following
> >>> >>>> output
> >>> >>>>
> >>> >>>> >>> db.session.add(user)
> >>> >>>> Traceback (most recent call last):
> >>> >>>>  File "<input>", line 1, in <module>
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/scoping.py",
> >>> >>>> line 113, in do
> >>> >>>>    return getattr(self.registry(), name)(*args, **kwargs)
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
> >>> >>>> line 1161, in add
> >>> >>>>    self._save_or_update_state(state)
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
> >>> >>>> line 1170, in _save_or_update_state
> >>> >>>>    self._save_or_update_impl(state)
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
> >>> >>>> line 1402, in _save_or_update_impl
> >>> >>>>    self._update_impl(state)
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
> >>> >>>> line 1394, in _update_impl
> >>> >>>>    self._attach(state)
> >>> >>>>  File
> "/usr/lib/python2.7/site-packages/sqlalchemy/orm/session.py",
> >>> >>>> line 1428, in _attach
> >>> >>>>    state.session_id, self.hash_key))
> >>> >>>> InvalidRequestError: Object '<User at 0x1a75910>' is already
> >>> >>>> attached
> >>> >>>> to session '15348048' (this is '15347920')
> >>> >>>>
> >>> >>>>
> >>> >>>> On Sun, Dec 4, 2011 at 5:32 PM, Andrey V. Martyanov
> >>> >>>> <realduke@gmail.com>
> >>> >>>> wrote:
> >>> >>>> > Hi!
> >>> >>>> >
> >>> >>>> > You should add your user object to the session:
> >>> >>>> >
> >>> >>>> >>> db.session.add(user)
> >>> >>>> >
> >>> >>>> > then commit:
> >>> >>>> >
> >>> >>>> >>> db.session.commit()
> >>> >>>> >
> >>> >>>> >
> >>> >>>> > On Mon, Dec 5, 2011 at 4:09 AM, Thomas Dziedzic <
> gostrc@gmail.com>
> >>> >>>> > wrote:
> >>> >>>> >>
> >>> >>>> >> I already have a user in a database with a field named
> >>> >>>> >> user.viewpassword which isn't displayed in __repr__.
> >>> >>>> >> The following is the series of commands I do:
> >>> >>>> >>
> >>> >>>> >> >>> from flask import Flask
> >>> >>>> >> >>> app = Flask(__name__)
> >>> >>>> >> >>> app.config['SQLALCHEMY_DATABASE_URI'] =
> >>> >>>> >> >>> 'mysql://root:tom123@localhost/idabble'
> >>> >>>> >> >>> from flaskext.sqlalchemy import SQLAlchemy
> >>> >>>> >> >>> db = SQLAlchemy(app)
> >>> >>>> >> >>> import models
> >>> >>>> >> >>> user =
> >>> >>>> >> >>> models.User.query.filter_by(email='tom@google.com
> ').first()
> >>> >>>> >> 2011-12-04 16:54:28,599 INFO sqlalchemy.engine.base.Engine
> SELECT
> >>> >>>> >> DATABASE()
> >>> >>>> >> 2011-12-04 16:54:28,600 INFO sqlalchemy.engine.base.Engine ()
> >>> >>>> >> 2011-12-04 16:54:28,603 INFO sqlalchemy.engine.base.Engine SHOW
> >>> >>>> >> VARIABLES LIKE 'character_set%%'
> >>> >>>> >> 2011-12-04 16:54:28,604 INFO sqlalchemy.engine.base.Engine ()
> >>> >>>> >> 2011-12-04 16:54:28,605 INFO sqlalchemy.engine.base.Engine SHOW
> >>> >>>> >> VARIABLES LIKE 'lower_case_table_names'
> >>> >>>> >> 2011-12-04 16:54:28,605 INFO sqlalchemy.engine.base.Engine ()
> >>> >>>> >> 2011-12-04 16:54:28,607 INFO sqlalchemy.engine.base.Engine SHOW
> >>> >>>> >> COLLATION
> >>> >>>> >> 2011-12-04 16:54:28,607 INFO sqlalchemy.engine.base.Engine ()
> >>> >>>> >> 2011-12-04 16:54:28,617 INFO sqlalchemy.engine.base.Engine SHOW
> >>> >>>> >> VARIABLES LIKE 'sql_mode'
> >>> >>>> >> 2011-12-04 16:54:28,617 INFO sqlalchemy.engine.base.Engine ()
> >>> >>>> >> 2011-12-04 16:54:28,618 INFO sqlalchemy.engine.base.Engine
> BEGIN
> >>> >>>> >> (implicit)
> >>> >>>> >> 2011-12-04 16:54:28,620 INFO sqlalchemy.engine.base.Engine
> SELECT
> >>> >>>> >> user.id AS user_id, user.email AS user_email, user.password AS
> >>> >>>> >> user_password, user.viewpassword AS user_viewpassword
> >>> >>>> >> FROM user
> >>> >>>> >> WHERE user.email = %s
> >>> >>>> >>  LIMIT %s, %s
> >>> >>>> >> 2011-12-04 16:54:28,621 INFO sqlalchemy.engine.base.Engine
> >>> >>>> >> ('tom@google.com', 0, 1)
> >>> >>>> >> >>> user
> >>> >>>> >>
> >>> >>>> >>
> >>> >>>> >>
> >>> >>>> >> <User('u'tom@google.com
> '','u'sha1$rshps9X0$ff4c48176df5c86f0042db0746479fbebacbbc66'')>
> >>> >>>> >> >>> user.viewpassword = 'hi'
> >>> >>>> >> >>> db.session.commit()
> >>> >>>> >>
> >>> >>>> >> As far as I know, this should work, but when I check my
> database,
> >>> >>>> >> user.viewpassword is still null.
> >>> >>>> >> Any ideas?
> >>> >>>> >
> >>> >>>> >
> >>> >>>
> >>> >>>
> >>> >>
> >>
> >>
> >
>