How to add fields dynamically in Django?

Question

I want to add fields dynamically in Django 1.8.

Here's my models.py

class Book(models.Model):
   title = models.CharField(max_length=100)

   def __str__(self):
        return self.title

class Author(models.Model):
   name = models.CharField(max_length=100)
   books = models.ManyToManyField(Book)

   def __str__(self):
        return self.name

Here's my admin.py

class AuthorAdmin(admin.ModelAdmin):
admin.site.register(Author, AuthorAdmin)

class BookAdmin(admin.ModelAdmin):
admin.site.register(Book, BookAdmin)

Here's how it looks now:

I've tried to use Inline, but I can only add a new book also.

I want to be able to add many books to one author dynamically. Something like this:

How can I do this?

Edit:

I've changed AuthorAdmin to this:

class AuthorAdmin(admin.ModelAdmin):
    formfield_overrides = {
        models.ManyToManyField: {'widget': CheckboxSelectMultiple},
    }
admin.site.register(Author, AuthorAdmin)

But instead of one checkbox with "N" options, I want "N" textboxes to choose the books.

bruno desthuilliers · Accepted Answer · 2016-01-13 15:23:44Z

You got your cardinalities the wrong way round. As you wrote it, the relationship is "An author has one book, a book has many authors", while you obviously wanted "A book has one author, an author has many books" - or possibly "a book as one or many authors, an author has one or many books".

In the first case, you have to remove the ForeignKey in Author and add a ForeignKey to Book in Author - and use an AdminInline in Author if you want to be able to add books to an author from the AuthorAdmin.

In the second case, you want a ManyToManyField, which can be in either Book or Author...

Shang Wang · Accepted Answer · 2016-01-13 15:19:20Z

1

You need to use ManyToMany field for books:

books = models.ManyToManyField(Book)

Django doc for ManyToMany.

answered Jan 13, 2016 at 15:19

Shang Wang

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1 Comment

bruno desthuilliers Over a year ago

A ManyToManyField implies that a Book can have more than one author. While it makes sense wrt/ "real world", it's not necessarily the appropriate domain model for the OP's application.

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