pre_delete and post_delete signals in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Django signal for actions before deleting an object.

Django

from django.db.models.signals import [1]

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

Apre_delete

Bpost_save

Cm2m_changed

Dpost_delete

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing pre_delete with post_delete

Importing unrelated signals like post_save

The pre_delete signal is sent just before a model's delete() method is called.

2fill in blank

medium

Complete the code to connect a function to the post_delete signal for a model named Book.

Django

post_delete.connect([1], sender=Book)

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

Ahandle_save

Bhandle_delete

Chandle_pre_delete

Dhandle_post_delete

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name for pre_delete instead of post_delete

Using unrelated function names

The function connected to post_delete should handle actions after deletion, so a name like handle_post_delete fits best.

3fill in blank

hard

Fix the error in the signal handler definition to accept the correct parameters for pre_delete.

Django

def my_handler([1], instance, **kwargs):
    print(f"Deleting {instance}")

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

Asender

Bself

Crequest

Dobj

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'self' as first argument in signal handlers

Using instance as first argument

Signal handlers receive sender as the first argument, not self or others.

4fill in blank

hard

Fill both blanks to create a pre_delete signal handler that prints the instance being deleted and connect it to the Author model.

Django

def [1](sender, instance, **kwargs):
    print(f"About to delete [2]")

pre_delete.connect(delete_notice, sender=Author)

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

Adelete_notice

Binstance

Csender

DAuthor

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching function name and connect argument

Printing sender instead of instance

The handler function is named delete_notice and it prints the instance being deleted.

5fill in blank

hard

Fill all three blanks to create a post_delete handler that logs the deleted object's ID and connect it to the Publisher model.

Django

def [1](sender, instance, [2]):
    print(f"Deleted object ID: {instance.[3]")

post_delete.connect(log_deletion, sender=Publisher)

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

Alog_deletion

B**kwargs

Cid

Dinstance

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting **kwargs parameter

Printing wrong attribute instead of id

The handler is named log_deletion, accepts **kwargs, and prints the id of the deleted instance.