How to Use Multiple Models in a Foreign Key Relationship?

Using Django Using the ORM
1

I would like to know how to do so that in my “Association” model, the “client” field displays the models “ClientIntermediaire, ClientDemiGros,ClientDetaillant” with relationship “ForeignKey”.

class Client(models.Model):

    name = models.CharField(blank=False, null=False, max_length=15)
    first_name = models.CharField(blank=False, null=False, max_length=30)
    phone_perso = PhoneNumberField(unique=True, null=False, blank=False)
    email = models.EmailField(blank=True, null=True, default=None, unique=True)
    city = models.CharField(null=False, blank=False, max_length=30)
    gps_longitude = models.DecimalField(max_digits=8, decimal_places=3, null=True, blank=True)
    gps_latitude = models.DecimalField(max_digits=8, decimal_places=3, null=True, blank=True)
    created_by= models.ForeignKey(User, on_delete=models.PROTECT)
    created_at = models.DateTimeField(auto_now_add=True)
    modified_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.first_name + ' ' + self.name

    class Meta:
        abstract = True

# Model of Client (Type = Intermediaire)
class ClientIntermediaire(Client):
    # Different statuses that a "Intermediaire" type customer can take
    STATUS_CLIENT = (('actif', 'Actif'), ('inactif', 'Inactif'), ('suspendu', 'Suspendu'))

    type_client = models.CharField(default="intermediaire", blank=False, null=False, editable=False, max_length=13)
    status = FSMField(default=STATUS_CLIENT[0])


class ClientDemiGros(Client):

    # Different statuses that a "Demi-gros" type customer can take
    STATUS_CLIENT = (('actif', 'Actif'), ('inactif', 'Inactif'),('suspendu', 'Suspendu'))

    type_client = models.CharField(default="demi-gros", max_length=13, blank=False, null=False, editable=False)
    intermediate = models.ForeignKey(ClientIntermediaire, on_delete=models.PROTECT, blank=True, null=False)
    status = FSMField(default=STATUS_CLIENT[0])


# Model to associate a phoneNumber to a Client
class Association(models.Model):
    number = models.ForeignKey(PhoneNumber, on_delete=models.PROTECT)
    client = models.ForeignKey((ClientIntermediaire, ClientDemiGros), on_delete=models.PROTECT)
2

Please do not post images of code here. They’re hard to read, and can’t be searched or quoted for commenting.
Copy/paste the code into the body of your message, surrounded by lines of three backtick - ` characters to maintain formatting. That means you’ll have a line of ```, then your code, then another line of ```.

From what I can read, it looks like you’ve got an error in your Association model - your definition of the client field is wrong. Also, you’re not showing your Client model here. Is it an abstract class or a concrete class?

Also, please clarify what you mean by your question. Are you asking how to create a template to show those fields when you’re displaying an instance of Association?

3

Sorry, I corrected the post.
In fact I want to be able to add the instances of the 02 models (ClientIntermediaire, ClientDemiGros) in the “Client” field in the “Association” model.

4

It doesn’t work that way. The client field is a ForeignKey to a related model. It is a reference to a model, it does not “contain” those instances. If you want two references (each to a different model), then you need two ForeignKey fields.

I don’t know what the actual relationship is supposed to be among these models, so I can’t provide any specific advice, but I suggest you re-evaluate how you have your models defined and what you’re trying to achieve by these relationships.

5

Okay, I understand. i will try to change my models.