I am having a problem with Django 2.2.7 and postgresql 12 using the command "python manage.py migrate".
When I execute it, the process fails with the following error: django.db.utils.ProgrammingError: there is no unique constraint matching given keys for referenced table "clients_clients"
I understand that this error indicates that when a field is used as a foreing key in another table, this field must be unique.
My model clients in Django is:
class Clients(models.Model):
name = models.CharField(max_length=60, unique=True)
document_num = models.CharField(max_length=15)
phone = models.CharField(max_length=15, blank=True)
email = models.EmailField(max_length=30, blank=True)
instagram = models.CharField(max_length=30, blank=True)
address = models.TextField(max_length=100, blank=True)
The model with the foreing key to the field "name" of clients_clients is:
class Budgets(models.Model):
date = models.DateField(error_messages={'null': "You must set a date"})
title = models.CharField(max_length=50, unique=True)
client = models.ForeignKey(Clients, null=True, on_delete=models.SET_NULL, to_field='name')
price = models.DecimalField(default=0, decimal_places=2, max_digits=10)
observations = models.TextField(max_length=200, blank=True)
As is shown above, the field "name" in model "Clients" is set as unique=True. But in spite of that, the error mentioned is shown.
Anyone can help me to understand why?