When typing: print(Topic.objects.all()) , I get the error message: django.db.utils.OperationalError: no such table:

hello after running this code in a models.py file:

from django.db import models

# Create your models here.
class Topic(models.Model):
    top_name = models.CharField(max_length=264,unique=True)

    def __str__(self):
        return self.top_name

class Webpage(models.Model):
    topic = models.ForeignKey(
        'Topic',
        on_delete=models.CASCADE,
    )
    name = models.CharField(max_length=264,unique=True)
    url = models.URLField(unique=True)

    def __str__(self):
        return self.name

class AccessRecord(models.Model):
    name = models.ForeignKey(
        'Webpage',
        on_delete=models.CASCADE,
    )
    date = models.DateField()

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

As a note, I was having trouble with migrations as I kept getting error messages related to the .ForeignKey so I got the following code from some other forum, and it finally ran the migrations but I’m not sure if this code is the problem…

topic = models.ForeignKey(
    'Topic',
    on_delete=models.CASCADE,
)

After successful migrations, I ran

python manage.py migrate

everything seemed to migrate fine. Then I ran

python manage.py shell

then I ran:

>>> from first_app.models import Topic
>>> print(Topic.objects.all())

but got the following error:

OperationalError: no such table: first_app_topic

here’s the full read out:

Traceback (most recent call last):
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/sqlit
e3/base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: first_app_topic

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/models/query.p
y", line 252, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/models/query.p
y", line 258, in __len__
    self._fetch_all()
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/models/query.p
y", line 1261, in _fetch_all
    self._result_cache = list(self._iterable_class(self))

File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/models/query.p
y", line 57, in __iter__

    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/models/sql/com
piler.py", line 1144, in execute_sql
    cursor.execute(sql, params)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 100, in execute
    return super().execute(sql, params)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/utils.py", lin
e 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/utils
.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "/Users/homepage/opt/anaconda3/envs/MyDjangoEnv/lib/python3.8/site-packages/django/db/backends/sqlit
e3/base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: first_app_topic

models.py is in:

My_Django_Stuff/first_project/first_app/migrations/models.py

any help would be greatly appreciated, I’ve read a bunch of other threads on this topic and some say to toss the db.sqlite3 and pycache – is this what I should do?

thnx

Answer

I believe that I fixed the problem by doing the following steps below:

python manage.py migrate

python manage.py makemigrations first_app

python manage.py migrate

python manage.py shell

from first_app.models import Topic

print(Topic.objects.all())

I believe that b4 I didn’t make the migrations apply to my first_app (the 2nd step) and then run the migration again(the 3rd step). Also I reinstalled django, this time with the pip installer and it seems to be working much better- as I was getting error messages b4. Right after I would install django in the app folder I was working in, it would say that it it can’t find django. This happened off and on. B4 I installed django with the command:

conda install django

but have been having problems with conda, I have to always paste:

PATH=/Users/aleong/opt/anaconda3/bin:$PATH

b4 I create a virtual env with:

conda create --name myDjangoEnv django

Also fixing the code in my models.py file as suggested by Somto (thnx Somto) helped, I replaced my code with:

topic = models.ForeignKey(Topic, on_delete= models.CASCADE)