DjangoAdmin TypeError：“str”和“int”的实例之间不支持“<”

Question

In a normal python program, I understand what this problem means but I am not able to find the reason behind this error while saving posts from admin in Django.

Have I given any invalid data according to field?

So while saving it gives the following error:

Environment:


Request Method: POST
Request URL: http://localhost:8000/admin/blog/post/add/

Django Version: 3.2.4
Python Version: 3.6.9
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'blog']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware']



Traceback (most recent call last):
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/contrib/admin/options.py", line 616, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/views/decorators/cache.py", line 44, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/contrib/admin/sites.py", line 232, in inner
    return view(request, *args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/contrib/admin/options.py", line 1657, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/utils/decorators.py", line 43, in _wrapper
    return bound_method(*args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/utils/decorators.py", line 130, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/contrib/admin/options.py", line 1540, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/contrib/admin/options.py", line 1579, in _changeform_view
    form_validated = form.is_valid()
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/forms/forms.py", line 175, in is_valid
    return self.is_bound and not self.errors
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/forms/forms.py", line 170, in errors
    self.full_clean()
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/forms/forms.py", line 374, in full_clean
    self._post_clean()
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/forms/models.py", line 413, in _post_clean
    self.instance.full_clean(exclude=exclude, validate_unique=False)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/db/models/base.py", line 1216, in full_clean
    self.clean_fields(exclude=exclude)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/db/models/base.py", line 1258, in clean_fields
    setattr(self, f.attname, f.clean(raw_value, self))
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 671, in clean
    self.run_validators(value)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 623, in run_validators
    v(value)
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/core/validators.py", line 358, in __call__
    if self.compare(cleaned, limit_value):
  File "/home/prython/2021/Django_thrpracticalGuide/venv/lib/python3.6/site-packages/django/core/validators.py", line 392, in compare
    return a < b

Exception Type: TypeError at /admin/blog/post/add/
Exception Value: '<' not supported between instances of 'str' and 'int'

Here is how my models.py file look like:

from django.core import validators
from django.db import models
from django.utils.text import slugify
from django.core.validators import MinValueValidator
# Create your models here.

class Tag(models.Model):
    caption = models.CharField(max_length=20)

    def __str__(self):
        return self.caption

class Author(models.Model):
    first_name = models.CharField(max_length=100)
    last_name = models.CharField(max_length=100)
    email_address = models.EmailField()

    def full_name(self):
        return f"{self.first_name} {self.last_name}"

    def __str__(self):
        return self.full_name()

class Post(models.Model):
    title = models.CharField(max_length=100)
    excrept = models.CharField(max_length=150)
    image_name = models.CharField(max_length=150)
    date = models.DateField(auto_now=True)
    slug = models.SlugField(unique=True)
    content = models.TextField(validators=[MinValueValidator(10)])
    author = models.ForeignKey(Author, on_delete=models.SET_NULL, null=True, related_name='posts')
    tags = models.ManyToManyField(Tag)
    
    def save(self, *args, **kwargs):
        self.slug = slugify(self.title)
        super().save(*args, **kwargs)
    
    def __str__(self):
        return self.title

Let me know if I need to send anyother file?

Answer 1

for TextField s you should use MinLengthValidator .

from django.core.validators import MinLengthValidator


class Post(models.Model):
    # ...
    content = models.TextField(validators=[MinLengthValidator(10)])
    # ...