OneToOneField for one-to-one in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a one-to-one relationship in Django models.

Django

class Profile(models.Model):
    user = models.[1](User, on_delete=models.CASCADE)

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

AForeignKey

BOneToOneField

CManyToManyField

DCharField

Attempts:

3 left

💡 Hint

Common Mistakes

Using ForeignKey instead of OneToOneField causes many profiles per user.

Using ManyToManyField allows multiple users per profile.

The OneToOneField creates a one-to-one relationship between models, meaning each Profile is linked to exactly one User.

2fill in blank

medium

Complete the code to specify the behavior when the related user is deleted.

Django

user = models.OneToOneField(User, on_delete=models.[1])

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

ACASCADE

BSET_NULL

CPROTECT

DDO_NOTHING

Attempts:

3 left

💡 Hint

Common Mistakes

Using SET_NULL without allowing null causes errors.

Using DO_NOTHING can leave orphaned profiles.

CASCADE means if the related User is deleted, the Profile will be deleted too, keeping data consistent.

3fill in blank

hard

Fix the error in the model field to ensure the one-to-one link is unique.

Django

user = models.OneToOneField(User, on_delete=models.CASCADE, [1]=True)

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

Anull

Bblank

Cunique

Drelated_name

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'null=True' does not enforce uniqueness.

Using 'blank=True' affects forms, not database uniqueness.

The OneToOneField is unique by default, but explicitly setting unique=True ensures uniqueness.

4fill in blank

hard

Fill both blanks to define a one-to-one field with a custom related name and allow null values.

Django

user = models.OneToOneField(User, on_delete=models.CASCADE, [1]=True, [2]='profile')

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

Anull

Bblank

Crelated_name

Dunique

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'blank' with 'null' for database nullability.

Not setting 'related_name' causes default reverse names.

null=True allows the field to be empty in the database. related_name='profile' lets you access the profile from the user with user.profile.

5fill in blank

hard

Fill all three blanks to create a one-to-one field with cascade delete, a custom related name, and allow blank values in forms.

Django

user = models.OneToOneField(User, on_delete=models.[1], related_name='[2]', [3]=True)

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

ACASCADE

Bprofile

Cblank

DPROTECT

Attempts:

3 left

💡 Hint

Common Mistakes

Using PROTECT instead of CASCADE changes delete behavior.

Confusing 'blank' with 'null' for form vs database.

on_delete=CASCADE deletes the profile if the user is deleted. related_name='profile' allows reverse access. blank=True lets forms accept empty input for this field.