Through model for extra fields on M2M in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a many-to-many relationship using a through model.

Django

class Book(models.Model):
    authors = models.ManyToManyField(Author, through=[1])

Drag options to blanks, or click blank then click option'

ABook

BBookAuthor

CAuthor

DAuthorBook

Attempts:

3 left

💡 Hint

Common Mistakes

Using the related model name instead of the through model.

Forgetting to define the through model class.

The through parameter should be the name of the intermediate model that holds extra fields.

2fill in blank

medium

Complete the through model with the correct field type for the foreign key to Book.

Django

class BookAuthor(models.Model):
    book = models.[1](Book, on_delete=models.CASCADE)

Drag options to blanks, or click blank then click option'

AForeignKey

BManyToManyField

COneToOneField

DCharField

Attempts:

3 left

💡 Hint

Common Mistakes

Using ManyToManyField inside the through model.

Using OneToOneField which restricts to one relation.

The through model uses ForeignKey fields to link to each related model.

3fill in blank

hard

Fix the error in the through model by completing the field for author.

Django

class BookAuthor(models.Model):
    author = models.[1](Author, on_delete=models.CASCADE)

Drag options to blanks, or click blank then click option'

AManyToManyField

BCharField

CForeignKey

DIntegerField

Attempts:

3 left

💡 Hint

Common Mistakes

Using CharField or IntegerField instead of ForeignKey.

Using ManyToManyField inside the through model.

The author field must be a ForeignKey to the Author model to link properly.

4fill in blank

hard

Fill both blanks to add an extra field and a string representation method in the through model.

Django

class BookAuthor(models.Model):
    book = models.ForeignKey(Book, on_delete=models.CASCADE)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
    [1] = models.IntegerField(default=0)

    def __str__(self):
        return f"[2] by [3] with contribution [1]%"

Drag options to blanks, or click blank then click option'

Acontribution

Bself.author

Cself.book

Dcontributor

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names or missing self in __str__ method.

Confusing attribute names.

The extra field is named contribution to store extra info. The string method uses self.book and self.author to show related objects.

5fill in blank

hard

Fill all three blanks to create a query that filters BookAuthor entries with contribution greater than 50.

Django

high_contrib = BookAuthor.objects.filter([1]__[2]=[3])

Drag options to blanks, or click blank then click option'

Acontribution

Bgt

C50

Dauthor

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names or lookup types.

Using single underscore instead of double underscore.

To filter by contribution greater than 50, use contribution__gt=50 in the filter.