Django 1.11: Can't get ManyToManyField to work - django

Question

I have the following models:
class Address(models.Model):
address1 = models.CharField(max_length=150, null=True)
address2 = models.CharField(max_length=150, null=True, blank=True)
city = models.CharField(max_length=50, null=True)
state_province = models.CharField(max_length=50, null=True)
zipcode = models.CharField(max_length=10, null=True)
country = models.CharField(max_length=3, default='USA', null=False)
created_at = models.DateTimeField(db_index=True, auto_now_add=True)
updated_at = models.DateTimeField(db_index=True, auto_now=True)
class Meta:
db_table = 'addresses'
and this one.....
class User(models.Model, AbstractBaseUser, PermissionsMixin):
email = models.EmailField(db_index=True, max_length=150, unique=True,
null=False)
first_name = models.CharField(max_length=45, null=False)
last_name = models.CharField(max_length=45, null=False)
mobile_phone = models.CharField(max_length=12, null=True)
profile_image = models.CharField(max_length=150, null=True)
is_staff = models.BooleanField(db_index=True, null=False, default=False)
is_active = models.BooleanField(
_('active'),
default=True,
db_index=True,
help_text=_(
'Designates whether this user should be treated as active. '
'Unselect this instead of deleting accounts.'
),
)
addresses = models.ManyToManyField(Address),
USERNAME_FIELD = 'email'
objects = MyCustomUserManager()
def __str__(self):
return self.email
def get_full_name(self):
return self.email
def get_short_name(self):
return self.email
class Meta:
db_table = 'users'
My first mystery is that by migrating the models, there is no "addresses" field in the users table, nor a pivot table in the database to keep the multiple relationships. How are ManyToMany payloads kept??
Secondly, my goal is to have multiple addresses for Users. I want Users to have multiple "Addresses" (and not each address having one User) because other models can have addresses too. I don't want the Address model to have 12 different "owner" fields with with ForeignKeys.
So. I try this:
from myApp.models import User
from myApp.models import Address
user = User(email="test#test.com", first_name="john", last_name="doe", mobile_phone="444")
# the model permits partial address fields, don't worry about that.
address = Address(city="New York", zipcode="10014")
Now I try to add the address to the user.addresses and I'm getting an error.
user.addresses.add(address)
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-5-0337af6b1cd4> in <module>()
----> 1 user.addresses.add(address)
AttributeError: 'tuple' object has no attribute 'add'
Help?

Answer 1

You have a superfluous comma after the definition of the many-to-many field, which turns it into a tuple. When you've removed this, you'll find both that the migrations will create your intermediary table, and that user.addresses.add() will work.