Refrain Django Models from creating an object after a specific count of that object in db is reached-CodePudding

I want to have a method to somehow show an error/prompt to the front end (could be json response), whenever user tries to add an object, in my case, 1 user cannot have more than 50 tasks stored inside the db, my db model is simple, it's just a task model, and a user model, each task has a foreign key user_id. I was doing it in golang-gorm using hooks, is there any similar method in Django to do so efficiently?

CodePudding user response：

You can override the clean method of your Task model in order to raise a ValidationError if the related user already has 50 tasks.

Something like this :

class Task(models.Model):
   user = models.ForeyKey(User, on_delete=models.CASCADE, related_name='tasks')

   def clean(self):
       if self.user.tasks.count() >= 50:
           raise ValidationError('User cannot have more than 50 tasks')