CODEWITHSUNDEEP
pythondjangodjango-models
Антон Игин
Антон Игин

Reputation: 195

'NOT NULL constraint failed' even with 'null=True'

I see this error when I run my code:

NOT NULL constraint failed: blog_post.category_id

Here is the code:

class Post(models.Model):
    class Meta:
        verbose_name='Запись'
        verbose_name_plural='Записи'

    author = models.ForeignKey('auth.User')
    category = models.ForeignKey('Theme', default=None, blank=True, null=True)
    title = models.CharField(max_length=200,verbose_name='Заголовок')
    text = RichTextField(verbose_name='Текст')
    created_date = models.DateTimeField(verbose_name='Время создания',default=timezone.now)
    published_date = models.DateTimeField(verbose_name='Время публикации',blank=True, null=True)


    def publish(self):
        self.published_date = timezone.now()
        self.save()
    def approved_commentimages(self):
        return self.comments.filter(approved_comment=True)

    def __str__(self):
        return self.title

class Theme(models.Model):
    class Meta:
        verbose_name='Категория'
        verbose_name_plural='Категории'

    title = models.CharField(verbose_name='Заголовок', max_length=40)
    slug = models.SlugField(verbose_name='Транслит', null=True)
    def __str__(self):
        return self.title

What am I do wrong?

Upvotes: 1

Views: 1960

Answers (1)

Marcus Lind
Marcus Lind

Reputation: 11450

This can happen if you delete or modify migration files, your actual database can get out of sync with your model files and when you run makemigrations it might say no changes detected, even though the file is different from the actual database.

You can verify this by logging into your MySQL database and check the actual null constraints. You will see that it probably says that it can't be null even though your file say it can.

The easiest solution to this is to just create a new database and run migrate. However if you already have a lot of data in your database and want to avoid making a new one and migrating your data, you can try to sync the database with your model again manually.

Upvotes: 3

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