Indeed something in the project's code must be wrong but it is not the
bi-directional ManyToMany as this has been working in django 1.4, 1.5, 1.6
and 1.7. One might want to had the ManyToMany in both models so to be able
to add more information, as it is stated in the django
docs
https://docs.djangoproject.com/en/1.9/topics/db/models/#extra-fields-on-many-to-many-relationships
in my case I just want the field to have a different name. I am thinking of
using a property but I got into some troubles with my code when I did that,
specifically the migration to remove the all_pizzas field crashes.
I have created a new project with only those 2 models and it seems to work
correctly, so the problem is somehow related to our test runner (py.test)
and something else which I still don't know.
My models.py file looks like this:
from django.db import models
class Pizza(models.Model):
available_toppings = models.ManyToManyField('Topping')
class Topping(models.Model):
all_pizzas = models.ManyToManyField(Pizza,
through=Pizza.available_toppings.through, verbose_name='available pizzas')
I will continue investigating.
On Friday, December 4, 2015 at 11:31:19 AM UTC+1, Remco Gerlich wrote:
>
> One, from that error message alone I can't figure out what is happening
> and why when you run tests, so I can't help there.
>
> But two: you don't have a ManyToManyField, you have TWO ManyToManyFields.
> If you define a many to many field on one model, than it's automatically
> also defined on the other (if you only have the one on Pizza, then you can
> do topping.pizza_set.all() from the other side.
>
> So your current code is almost certainly wrong, but if these are your
> exact models than I don't think they are related to your error.
>
> Remco
>
> On Fri, Dec 4, 2015 at 9:54 AM, filias <filipa....@gmail.com <javascript:>
> > wrote:
>
>> Hi,
>>
>> I have recently upgraded to sjango 1.8 and I have 2 models with a
>> bi-directional ManyToMany field. It looks like this
>>
>> class Pizza(Model):
>> available_toppings = ManyToManyField('Topping')
>>
>> class Topping(Model):
>> all_pizzas = ManyToManyField(Pizza,
>> through=Pizza.available_stoppings.through, verbose_name='available pizzas')
>>
>> Everything was fine in django 1.7 but right now when running tests,
>> specifically when creating the test database, I get this exception:
>>
>> self = <django.db.backends.sqlite3.base.SQLiteCursorWrapper object at
>> 0x7fd24fca4b00>
>>
>> def execute(self, query, params=None):
>> if params is None:
>>
>> > return Database.Cursor.execute(self, query)
>> E OperationalError: table "products_pizza_available_toppings"
>> already exists
>>
>> So it looks like the creation of the test database is trying to re-create
>> the intermediate table for the ManyToMany.
>>
>> I do not get any exception when running my site.
>>
>> Does anyone know how can I fix this?
>>
>> Thank you in advance
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "Django users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to django-users...@googlegroups.com <javascript:>.
>> To post to this group, send email to django...@googlegroups.com
>> <javascript:>.
>> Visit this group at http://groups.google.com/group/django-users.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/django-users/4b8bb3c4-c0bd-4315-9cb6-004db2fa2355%40googlegroups.com
>>
>> <https://groups.google.com/d/msgid/django-users/4b8bb3c4-c0bd-4315-9cb6-004db2fa2355%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
--
You received this message because you are subscribed to the Google Groups
"Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-users+unsubscr...@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at http://groups.google.com/group/django-users.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-users/0d982fc9-aebb-4430-aa56-28babd1fcee8%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
