How to do Django Chained Select In Forms.py?

Question

class Library(forms.ModelForm):

    author = forms.ChoiceField(
        widget = forms.Select(),
        choices = ([
            ('Jk Rowling','Jk Rowling'), 
            ('agatha christie','agatha christie'),
            ('mark twain','mark twain'), 
        ]),
        initial = '1', 
        required = True,
    )
    books = forms.ChoiceField(
        widget = forms.Select(), 
        choices = ([
            ('Harry Potter 1','Harry Potter 1'),  # 1
            ('Harry Potter 2','Harry Potter 2'),  # 2
            ('Harry Potter 3','Harry Potter 3'),  # 3
            ('Harry Potter 4','Harry Potter 4'),  # 4
            ('The A.B.C. Murders','The A.B.C. Murders'),  # 5
            ('Dumb Witness','Dumb Witness'),  # 6
            ('Death on the Nile','Death on the Nile'),  # 7
            ('Murder Is Easy','Murder Is Easy'),  # 8
            ('Roughing It','Roughing It'),  # 9
            (' The Gilded Age ',' The Gilded Age '),  # 10
            ('Adventures of Tom Sawyer','Adventures of Tom Sawyer'),  # 11
        ]),
        initial = '1',
        required = True,
    )

If User Select the Author As Jk Rowling the harry potter series must be populated in the books choice field (1 to 4 choices)

If User select the Author As Agatha Christie Then only the (5 to 8 )must be populated in the books choice field

If User select the Author As Mark Twain Then only the ( 8 to 11 ) choice must be populated in the select widget of the books choice field

I want to filter the choices can anyone help ?

Answer 1

Keep author and books in DB.

models.py

Class Author(models.Model):
    name = models.CharField(max_length=50)
    ......

class Books(models.Model):
    ....
    author = models.ForeignField(Author)
    ....

Class Library(models.Model):
    .....
    author = models.ForeignKey(Author)
    books = models.ForeignKey(Books)
    .....

forms.py

class Library(forms.ModelForm):

    def __init__(self, *args, **kwargs):
        super(Library, self).__init__(*args, **kwargs)
        self.fields['author'].choices = list(Author.objects.values_list('id', 'name'))

        self.fields['books'].choices = list(Books.objects.values_list('id', 'name'))


    class Meta:
        Model: Library

Based on Author selection, trigger from ajax call and get all the corresponding books.