Das deutsche Python-Forum

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from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=255)
    authors = models.ManyToManyField("Author", related_name="books")

    def __str__(self):
        return self.title

class Author(models.Model):
    name = models.CharField(max_length=255, unique=True)

    def __str__(self):
        return self.name

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from books.models import Author, Book
book1 = Book(title='Python unchained', authors='Guido van Rossum')

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TypeError: Direct assignment to the forward side of a many-to-many set is prohibited. Use authors.set() instead

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from books.models import Author, Book
book1 = Book(title='Python unchained')
book1.save()
book1.authors.add(Author.objects.get(name="Guido van Rossum"))

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# zwei Autoren
book1.authors.add(Author.objects.get(name="Guido van Rossum"), Author.objects.get(name="2nd Author"))