Self-referencing relationships in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a self-referencing ForeignKey in a Django model.

Django

class Category(models.Model):
    name = models.CharField(max_length=100)
    parent = models.ForeignKey('[1]', on_delete=models.CASCADE, null=True, blank=True)

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

A'Category'

B'self'

C'models'

D'parent'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the model class name directly without quotes.

Using an unrelated string instead of 'self'.

In Django, to create a self-referencing ForeignKey, you use the string 'self' to refer to the same model class.

2fill in blank

medium

Complete the code to allow a Category to have many children categories.

Django

class Category(models.Model):
    name = models.CharField(max_length=100)
    parent = models.ForeignKey('self', on_delete=models.CASCADE, null=True, blank=True, related_name=[1])

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

A'children'

B'parents'

C'siblings'

D'categories'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'parents' which is the opposite direction.

Using unrelated names like 'siblings'.

The related_name defines the reverse relation name. 'children' is a common choice for self-referencing parent-child relations.

3fill in blank

hard

Fix the error in the model field to correctly allow null parent categories.

Django

parent = models.ForeignKey('self', on_delete=models.CASCADE, [1]=True, blank=True, related_name='children')

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

Aallow_null

Bempty

Cnull

Dnullable

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'nullable' instead of 'null'.

Confusing 'blank' with 'null'.

The correct argument to allow a ForeignKey to be empty in the database is null=True.

4fill in blank

hard

Fill both blanks to create a self-referencing ManyToManyField with a symmetrical relationship.

Django

class Person(models.Model):
    name = models.CharField(max_length=100)
    friends = models.[1]('self', [2]=True, blank=True)

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

AManyToManyField

BForeignKey

Csymmetrical

Drelated_name

Attempts:

3 left

💡 Hint

Common Mistakes

Using ForeignKey instead of ManyToManyField.

Forgetting to set symmetrical=True for self-referencing many-to-many.

A self-referencing ManyToManyField uses symmetrical=True to indicate the relationship is mutual, like friendship.

5fill in blank

hard

Fill all three blanks to define a self-referencing ManyToManyField with an asymmetrical relationship and a custom reverse name.

Django

class Employee(models.Model):
    name = models.CharField(max_length=100)
    mentors = models.[1]('self', symmetrical=[2], [3]='mentees', blank=True)

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

AManyToManyField

BFalse

Crelated_name

DTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Setting symmetrical=True for an asymmetrical relation.

Not providing a related_name for reverse access.

Using ForeignKey instead of ManyToManyField.

For a mentorship relation, the ManyToManyField is asymmetrical (symmetrical=False) and uses related_name='mentees' for reverse access.