# Django Design Patterns (Django)

> Repository pattern, Service layer, Factory pattern, Strategy pattern, SOLID principles, clean architecture

- 24 interview questions
- Senior
- [Interview Questions: Django](https://sharpskill.dev/en/technologies/django/interview-questions.md)

## 1. What is the main objective of the Service Layer pattern in a Django application?

**Answer**

The Service Layer pattern encapsulates business logic in a dedicated layer, separate from views and models. This separation improves testability since logic can be tested independently, facilitates code reuse across different views or commands, and keeps views thin by delegating complex operations to services. This respects the Single Responsibility Principle (SRP).

## 2. What does the Repository Pattern abstract in a Django application?

**Answer**

The Repository Pattern provides an abstraction between the business layer and data access layer. It encapsulates Django ORM queries in explicit methods, allowing easy data source changes without modifying business logic. This also facilitates unit testing by enabling repository mocking instead of the actual database.

## 3. Which SOLID principle is violated when a Django view contains validation, business logic, and email sending all together?

**Answer**

The Single Responsibility Principle (SRP) states that a class or function should have only one reason to change. A view handling validation, business logic, and email sending has at least three distinct responsibilities. Any change in one of these areas would require modifying the view, making the code fragile and difficult to maintain.

## 21 more questions available

- How is the Factory Pattern typically used in a Django application?
- What is the main advantage of the Strategy Pattern for implementing different payment methods in Django?

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## Other Django interview topics

- [Python Basics](https://sharpskill.dev/en/technologies/django/interview-questions/python-basics.md): 25 questions, Junior
- [Python OOP](https://sharpskill.dev/en/technologies/django/interview-questions/python-oop.md): 20 questions, Junior
- [Django Fundamentals](https://sharpskill.dev/en/technologies/django/interview-questions/django-fundamentals.md): 20 questions, Junior
- [Django Models - Basics](https://sharpskill.dev/en/technologies/django/interview-questions/django-models-basics.md): 22 questions, Junior
- [Django Views](https://sharpskill.dev/en/technologies/django/interview-questions/django-views.md): 20 questions, Junior
- [Django Templates](https://sharpskill.dev/en/technologies/django/interview-questions/django-templates.md): 18 questions, Junior
- [Django Forms](https://sharpskill.dev/en/technologies/django/interview-questions/django-forms.md): 22 questions, Mid-Level
- [Advanced QuerySets](https://sharpskill.dev/en/technologies/django/interview-questions/django-querysets.md): 25 questions, Mid-Level
- [Django Authentication](https://sharpskill.dev/en/technologies/django/interview-questions/django-authentication.md): 22 questions, Mid-Level
- [Django Middleware](https://sharpskill.dev/en/technologies/django/interview-questions/django-middleware.md): 18 questions, Mid-Level
- [Django Admin](https://sharpskill.dev/en/technologies/django/interview-questions/django-admin.md): 20 questions, Mid-Level
- [Django REST Framework](https://sharpskill.dev/en/technologies/django/interview-questions/django-rest-framework.md): 30 questions, Mid-Level
- [Django Signals](https://sharpskill.dev/en/technologies/django/interview-questions/django-signals.md): 18 questions, Mid-Level
- [File Upload](https://sharpskill.dev/en/technologies/django/interview-questions/django-file-upload.md): 20 questions, Mid-Level
- [Django Caching](https://sharpskill.dev/en/technologies/django/interview-questions/django-caching.md): 20 questions, Mid-Level
- [Django Sessions](https://sharpskill.dev/en/technologies/django/interview-questions/django-sessions.md): 18 questions, Mid-Level
- [Django Email](https://sharpskill.dev/en/technologies/django/interview-questions/django-email.md): 18 questions, Mid-Level
- [Django Testing](https://sharpskill.dev/en/technologies/django/interview-questions/django-testing.md): 22 questions, Mid-Level
- [Django Security](https://sharpskill.dev/en/technologies/django/interview-questions/django-security.md): 22 questions, Mid-Level
- [Django Deployment](https://sharpskill.dev/en/technologies/django/interview-questions/django-deployment.md): 24 questions, Mid-Level
- [Advanced Django ORM](https://sharpskill.dev/en/technologies/django/interview-questions/django-orm-advanced.md): 28 questions, Senior
- [Django Performance](https://sharpskill.dev/en/technologies/django/interview-questions/django-performance.md): 24 questions, Senior
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- [Settings & Production Configuration](https://sharpskill.dev/en/technologies/django/interview-questions/django-settings-configuration.md): 22 questions, Senior
- [Observability & Monitoring](https://sharpskill.dev/en/technologies/django/interview-questions/django-observability.md): 24 questions, Senior

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