Classes and OOP

Last reviewed May 28, 2026 Content v20260528

Track mode: server_script
Means: Server runner
Reading: ~1 min
Level: beginner

This lesson

This lesson teaches Classes and OOP: the syntax, APIs, and habits you need before advancing in Django.

Frameworks like Laravel are OOP-first—classes, visibility, and inheritance show up in every code review.

You will apply Classes and OOP in contexts like: SaaS dashboards, CMS-style products, internal tools, and APIs paired with React or mobile clients.

Write Python 3 in the editor and click Run on server—the dev runner executes your script; Django framework lessons also use local startproject for full MVT (LEARNING_RUNNER_ENABLED=true).

When you can explain the previous lesson's ideas without copying starter code.

Every Django model is a Python class inheriting from models.Model. Class-based views (CBVs) encapsulate HTTP handling in classes. OOP is central—not optional.

Model classes

class Article(models.Model):
    title = models.CharField(max_length=200)
    def __str__(self):
        return self.title

__str__ improves admin and shell readability. Add methods for domain logic: def is_published(self): ...

Inheritance

Abstract base models share fields across apps
CBVs inherit from View, ListView, CreateView
Proxy models change behavior without new tables

Important interview questions and answers

Q: FBV vs CBV?
A: Function-based views are explicit; class-based views reuse generic patterns (list, detail, form)—pick clarity over cleverness.
Q: What is Meta on a model?
A: Inner class for options: ordering, verbose_name_plural, db_table.
Q: __str__ vs __repr__?
A: __str__ for humans (admin); __repr__ for developers debugging in shell.

Self-check

What do all Django models inherit from?
Why define __str__ on a model?

Interview prep

FBV vs CBV?: Function views are explicit; class-based views reuse generic patterns (ListView, CreateView)—pick clarity over abstraction for complex flows.

Interview tip Lesson completion confidence

Can you explain this lesson in 30 seconds without reading notes?

Self-reflection (saved on this device)

Not saved yet.

Playground

Runs on the configured server runner (dev: npm run runner with LEARNING_RUNNER_ENABLED=true). Output appears below the editor.

Code runner not available

Server runner is disabled. Set LEARNING_RUNNER_ENABLED=true and LEARNING_RUNNER_URL in .env (see .env.example).

Check yourself

Multiple choice — immediate feedback.

Discussion

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self meaning?
Inheritance for models?

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