Django create a 'back' function

Question

I'm currently working on a CS project that works similar to kickstarter, which the user can back their projects. I already had a follow function which allows the user to follow their favorite projects, the model is shown below:

class Team(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='team')
following = models.ManyToManyField(settings.AUTH_USER_MODEL, related_name='followers', blank=True)

There is a function in my view.py that adds the user to the MANYTOMANY field if the user clicks 'follow' button.

My question is how should my 'back' model be structured? I need to store the amount the user backed this project, or 'team' in this case, and date they backed. Create a model for 'follow' function wasn't that hard because I didn't need to store any additional data other than just User. But for 'BACK' function, I need to store some additional data like 'date backed', 'amount backed'.

Answer 1

You can use a ManyToManyField with through

In your case, it would be something like this:

class Team(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, related_name='team')
    following = models.ManyToManyField(settings.AUTH_USER_MODEL,   related_name='followers', blank=True)
    backers = models.ManyToManyField(settings.AUTH_USER_MODEL, through='Backer', related_name='backers', blank=True)

class Backer(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL)
    team = models.ForeignKey('Team', related_name='team')
    amount = models.FloatField()
    date_joined = models.DateField()

and then to add backers:

backer = Backer(user=some_user, team=some_team, date_joined=date(2017, 02, 22), amount=200)

and you can get the backers on Team through the ManyToManyField :

SomeTeam.backers.all()
>>> <QuerySet [<User: Some User>]>