I try to populate a many-to-many field. The Relationship exists between the Menus and Course Model. I added some custom fields to the M2M Table, so I can store the order of the courses and their type (i.e. Starter, Appetizer, etc.). To get a dynamic webform, I use modelformset_factory with the python-formset-…
Tag: many-to-many
Flitering django queryset based on ManyToManyField
In my Request model, there is a field requested_to which is a ManyToManyField I want to filter queryset of Request model where a organization_user is not in requested_to Answer You can filter with: Django makes LEFT OUTER JOINs when you filter on a ManyToManyField (or a reverse ForeignKey), so here we exclude…
Using SQLAlchemy, I need to assign users into pools, and a ranking for each pool they’re in
Here is the relevant code. I’m writing a Flask application where users can join pools and compete against others within those pools (currently, pools and users are in a many to many relationship). Each user will need a rating for each pool that he/she is in (Elo Rating), and I’m not sure how to im…
Django order a query by instance of ManyToMany
I have a model A with a ForeignKey to B: A ManyToMany relationship with an extra field that weight any B and C relation: And I need to order the A model (A.objects.filter(…)) using the weight of B2C for a given instance of C. For only one A instance I can do : But I don’t know how to do
Self-referencing many-to-many relationship with an association object in SQLAlchemy
I’ve found examples for a self-referencing many-to-many relationship with an association table. How can I achieve the same using an association object? The code below is based on: How can I achieve a self-referencing many-to-many relationship on the SQLAlchemy ORM back referencing to the same attribute?…
Django 1.7: how to make ManyToManyField required?
I have a Django Model with ManyToManyField in it. I need to require user to select at least one M2M value in this field. I tried to set blank=False to M2M field but it didn’t help. I can solve this situation with custom Form definition or with override save() method for Person model. Is it possible to p…
How to add column in ManyToMany Table (Django)
From the example of Django Book, I understand if I create models as following: The Django would create a new table(A_B) beyond Table A, which has three columns: id a_id b_id But now I want to add a new column in the Table A_B, thus would be very easy if I use normal SQL, but now anyone can help me