Hi Simon, thanks for your reply, I suspected exactly what you said. I am not sure, this is not my code so I am not aware of the reason for this but I will try to refactor it the way you suggest.
Cheers, filipa On Friday, December 4, 2015 at 4:38:41 PM UTC+1, Simon Charette wrote: > > Hi filias, > > I personally didn't know one could define a reverse foreign key this way > and > I doubt this use case is covered by the test suite. I'm afraid it worked > for > Django < 1.8 by chance since it's not documented you can re-use the > implicitly created intermediary model as a `through` argument. I suspect > this > might be due to the `_meta`[1] refactoring that happened in 1.8. > > May I ask you why you don't simply define a `related_name`[2] if you simply > want to have a different reverse relationship name? > > class Pizza(models.Model): > pass > > class Topping(models.Model): > all_pizzas = models.ManyToManyField( > Pizza, related_name='available_toppings', > verbose_name='available pizzas' > ) > > Cheers, > Simon > > [1] https://docs.djangoproject.com/en/1.8/releases/1.8/#model-meta-api > [2] > https://docs.djangoproject.com/en/1.8/ref/models/fields/#django.db.models.ManyToManyField.related_name > > Le vendredi 4 décembre 2015 07:08:51 UTC-5, filias a écrit : >> >> 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 <[email protected]> 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 [email protected]. >>>> To post to this group, send email to [email protected]. >>>> 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. 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