Is Python Camelot tied to Elixir?

Question

The docs for Camelot say that it uses Elixir models. Since SQLAlchemy has included declarative_base for a while, I had used that instead of Elixir for another app. Now I would like to use the SQLAlchemy/declarative models directly in Camelot.

There is a post on Stackoverflow that says Camelot is not tied to Elixir and that using different models would be possible but it doesn't say how.

Camelot's original model.py only has this content:

import camelot.types
from camelot.model import metadata, Entity, Field, ManyToOne, OneToMany, Unicode, Date, Integer, using_options
from camelot.view.elixir_admin import EntityAdmin
from camelot.view.forms import *

__metadata__ = metadata

I added my SQLAlchemy model and changed model.py to this:

import camelot.types
from camelot.model import metadata, Entity, Field, ManyToOne, OneToMany, Unicode, Date, using_options
from camelot.view.elixir_admin import EntityAdmin
from camelot.view.forms import *

from sqlalchemy import Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

__metadata__ = metadata
Base = declarative_base()

class Test(Base):
    __tablename__ = "test"
    id = Column(Integer, primary_key=True)
    text = Column(String)

It didn't work. When I start main.py, I can see the GUI and Test in the sidebar, but can't see any rows. This is the tail of the traceback:

File "/usr/lib/python2.6/dist-packages/camelot/view/elixir_admin.py", line 52, in get_query
    return self.entity.query
AttributeError: type object 'Test' has no attribute 'query'

This is the elixir_admin.py code for line 46-52:

@model_function
def get_query(self):
    """:return: an sqlalchemy query for all the objects that should be
    displayed in the table or the selection view.  Overwrite this method to
    change the default query, which selects all rows in the database.
    """
    return self.entity.query

If this code is causing the problem, how do I overwrite the method to change the default query to make it work?

How can you use SQLAlchemy/declarative models in Camelot?

The code is above. I added the original `model.py` code so that you can see the difference. — boadescriptor, Mar 12 '12 at 13:00
Yes but i didnt find any statement where your code is trying to access `query` attribute of `Test`. Please post your traceback. — Nilesh, Mar 12 '12 at 13:06

score 2 · Accepted Answer · answered Mar 24 '12 at 15:47

Here is some sample code on using Declarative to define a Movie model for Camelot, some explanation can be found here.

import sqlalchemy.types
from sqlalchemy import Column
from sqlalchemy.ext.declarative import ( declarative_base, 
                                         _declarative_constructor )

from camelot.admin.entity_admin import EntityAdmin
from camelot.model import metadata
import camelot.types

from elixir import session

class Entity( object ):

    def __init__( self, **kwargs ):
        _declarative_constructor( self, **kwargs )
        session.add( self )

Entity = declarative_base( cls = Entity, 
                           metadata = metadata,
                           constructor = None )

class Movie( Entity ):

    __tablename__ = 'movie'

    id = Column( sqlalchemy.types.Integer, primary_key = True )
    name = Column( sqlalchemy.types.Unicode(50), nullable = False )
    cover = Column( camelot.types.Image(), nullable = True )

    class Admin( EntityAdmin ):
        list_display = ['name']
        form_display = ['name', 'cover']

score 1 · Answer 2 · answered Mar 12 '12 at 14:58

1

Which version of Camelot are you using ?

With the current version of Camelot (11.12.30) it is possible to use Declarative through some hacks. The upcoming version will make it much easier, while after this, the examples will be ported to Declarative as well.

answered Mar 12 '12 at 14:58

Erik

66
1

Good to know it will be ported to Declarative in the future! I'm using 10.07 through the distribution's package manager. Any way to make declarative work with it? – boadescriptor Mar 12 '12 at 15:02
1

For a new project I would advise not to use 10.07. Because the custom actions are much more flexible in 11.12. It's much easier to just easy_install camelot than to try some workarounds. – Erik Mar 12 '12 at 15:19
I couldn't use the easy_install version because it caused problems with the installed version of PyQT. – boadescriptor Mar 12 '12 at 15:29
1

What kind of problems ? Please take into account that recent PyQt versions (of mid 2011 and later) contain important bugfixes. – Erik Mar 12 '12 at 15:43
I managed to install the latest version of Camelot and PyQT. Camelot looks even better than before but I still need to use my old declarative SQLAlchemy models... You said there is a hack to do it, could you explain how it works? – boadescriptor Mar 16 '12 at 07:49

Is Python Camelot tied to Elixir?

2 Answers2