django.db.utils.IntegrityError:

Question

django.db.utils.IntegrityError: The row in table \'main_tutorial\' with primary key \'1\' has an invalid foreign key: main_tutorial.tutorial_series_id contains a

Answer 1

In your Tutorial model, you are using a default value for the foreign key field ** tutorial_series **. This causes the migration to check if a record in TutorialSeries exists with id=1 but there is no such data present, so the error is occuring.

To avoid the error while migrating, remove the on_delete=models.SET_DEFAULT and default=1 from our fields to make your models as:

class TutorialSeries(models.Model):
    tutorial_series = models.CharField(max_length=200)
    tutorial_category = models.ForeignKey(TutorialCategory,verbose_name="Category")
    series_summary = models.CharField(max_length=200)

    class Meta:
        #Otherwise we get "Tutorial Serie*ss* in admin"
        verbose_name_plural = "Series"

    def __str__(self):
        return self.tutorial_series

class Tutorial(models.Model):
        tutorial_title = models.CharField(max_length=200)
        tutorial_content = models.TextField()
        tutorial_published = models.DateTimeField("date published", default = datetime.now())
        tutorial_series = models.ForeignKey(TutorialSeries, verbose_name="Series", blank=True, null=True) #<--changes
        tutorial_slug = models.CharField(max_length=200,default=1)

        def __str__(self):
            return self.tutorial_title

After this, migrate your models. Then add data to TutorialCategory and TutorialSeries with id=1.

Then revert your models to your initial setup (keeping default=1 and on_delete=models.SET_DEFAULT). Then again run makemigrations and migrate your models. After this, your problem might be solved.