all() and filter() methods in Django - Mini Project: Build & Apply

Using all() and filter() Methods in Django QuerySets

📖 Scenario: You are building a simple Django app to manage a library's book collection. You want to retrieve all books and then filter books based on their availability status.

🎯 Goal: Learn how to use Django's all() method to get all records and filter() method to get specific records from the database.

📋 What You'll Learn

Create a Django model named Book with fields title (string) and is_available (boolean).

Use Book.objects.all() to get all books.

Use Book.objects.filter(is_available=true) to get only available books.

Assign the results to variables named all_books and available_books respectively.

💡 Why This Matters

🌍 Real World

Managing and querying data in a Django web application, such as listing all items or filtering items based on user needs.

💼 Career

Understanding Django QuerySets and how to retrieve data efficiently is essential for backend web development roles using Django.

1

Create the Book model

Create a Django model called Book with a title field as models.CharField(max_length=100) and an is_available field as models.BooleanField(default=true).

Django

# Define the Book model here
# Your code here

Need a hint?

Use Django's models.Model as the base class. Define title as a CharField and is_available as a BooleanField with default true.

2

Retrieve all books using all()

Write a line to get all Book records using Book.objects.all() and assign it to a variable called all_books.

Django

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)
    is_available = models.BooleanField(default=true)

# Get all books
# Your code here

Need a hint?

Use Book.objects.all() to get all book records and assign it to all_books.

3

Filter available books using filter()

Write a line to get only books where is_available is true using Book.objects.filter(is_available=true) and assign it to a variable called available_books.

Django

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)
    is_available = models.BooleanField(default=true)

all_books = Book.objects.all()

# Get only available books
# Your code here

Need a hint?

Use Book.objects.filter(is_available=true) to get only available books and assign it to available_books.

4

Complete the Django QuerySet usage

Add a comment above each variable to describe what it holds: # All books above all_books and # Available books above available_books.

Django

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)
    is_available = models.BooleanField(default=true)

# Add comments describing the variables below
# Your code here

Need a hint?

Simply add comments above each variable to explain what they store.