Question

I want to create an object in Django before calling the save method. This object will be created from a ForeignKey Value, I’ve changed the foreignkey field to look like an input field in order to write a value instead of selecting it.

I have 2 classes in 2 different model files

class Category(models.Model):
    title = models.ForeignKey(Title, verbose_name="Title")

and

class Title(models.Model):
    title = models.CharField("Title", primary_key=True, max_length=200)

When I create a category, I have to pick or write a title that already exists in the database and when I try to create a category with a new title I get this error :

Select a valid choice. That choice is not one of the available choices.

What I want to do is creating a title based on what I write in the ForeignKey field before creating the category so it can be used immediately.

I tried to redefine the save method to save the title object before saving the category but it didn’t work.

Any help will be really appreciated.

Thank you

Answer 1

You should probably consider putting the code to create Category entries in the model’s manager:

class CategoryManager(Manager):
    def create_category(category, title):
        t = Title.objects.get_or_create(title=title)
        return self.create(title=t)

class Category(models.Model):
    title = models.ForeignKey(Title, verbose_name="Title")
    objects = CategoryManager()

Then use create_category every time you want to create a Category.