CODEWITHSUNDEEP
djangodjango-users
Spatial Digger
Spatial Digger

Reputation: 1993

Making use of the users table, causing an error

In Django (2.x) I have an entry form, the model is here:

from django.db import models
from django.contrib.auth.models import User
from django.conf import settings

class Sample(models.Model):
    sample_id = models.AutoField(primary_key=True)
    area_easting = models.IntegerField()
    area_northing = models.IntegerField()
    context_number = models.IntegerField()
    sample_number = models.IntegerField()
    # taken_by = models.IntegerField()
    taken_by = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete = models.PROTECT)

    def __str__(self):
        return str(self.sample_id)

    class Meta:
        db_table = 'samples\".\"sample'
        #ordering = ["sample_id"]
        managed = False
        #verbose_name_plural = "samples"

This works as expected, a list of usernames drops down (while I would like to format - firstname lastname). However, when I return to the main viewing page I see an error.

django.db.utils.ProgrammingError: column sample.taken_by_id does not exist
LINE 1: ...text_number", "samples"."sample"."sample_number", "samples"....
                                                             ^
HINT:  Perhaps you meant to reference the column "sample.taken_by".

Clearly Django is adding the _id to the table name causing the error, I expect because it is a foreign key.

Any ideas how to remedy this behaviour?

Upvotes: 0

Views: 33

Answers (2)

Daniel Roseman
Daniel Roseman

Reputation: 599630

You can explicitly set the underlying db column via the db_column attribute:

taken_by = models.ForeignKey(settings.AUTH_USER_MODEL, db_column='taken_by', on_delete=models.PROTECT)

Upvotes: 1

Jc Din
Jc Din

Reputation: 77

https://docs.djangoproject.com/en/2.1/ref/models/fields/#database-representation

^ link to the docs where it specifies that it creates a _id field.

based from the error message you have posted. It seems that your database schema is not updated.

you might need to do manage makemigrations and migrate to apply your model changes to your db schema

e.g

$ python manage.py makemigrations
# to apply the new migrations file
$ python manage.py migrate

Upvotes: 0

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