Django relations between Models

Question

What I currently have in my models is this:

class Project(models.Model):
 project_name = models.CharField(max_length=255, unique=True, blank=False)
 def __str__(self):
 return str(self.project_name)
class Profile(models.Model):
 user = models.OneToOneField(User, on_delete=models.CASCADE) 
 role = models.CharField(choices=ROLE_CHOICES, max_length=255, default='Agent')

Now my question is: Users should be able to have multiple Projects - so I obviously can't use a OneToOne-Field in the Profile-Model.

Later I want to use it for example to just show a user news which are only related to the projects he participates in.

What would be the best strategy to make this possible? Any input is highly appreciated.

• Paulo Almeida: There are several ways to do it, depending on the objective. You say users should be able to have multiple projects; should projects also have multiple users? If so, you can add a ManyToManyField on Project. If not, it should be a ForeignKey. If it's a ManyToManyField, it can be on either Project or Profile, but I think semantically it makes more sense on Project, linking it to the User, and not to the Profile.
• Tobi: @PauloAlmeida Interesting thoughts! The ManyToManyField is exactly what I needed. I will try to find out which link makes more sense on the later use to keep stuff as simple as possible. Thank you for your help!

Answer 1

Use ManyToMany on project.

class Profile(models.Model):
 user = models.OneToOneField(User, on_delete=models.CASCADE) 
 role = models.CharField(choices=ROLE_CHOICES, max_length=255, default='Agent')
 project = models.ManyToManyField(Project)

This way one profile can have as many project as he/she wants

On your view you can use this field to filter based on project

• Tobi: Thank you very much, you removed the knot that was inside my brain. ;) Just to make it complete: project = models.ManyToManyField(Project)
• Walucas: @Tobi right! I just fixed the code.... if that answer your question, consider accepting the answer :)