If you’re trying to keep up with technological advances and want your products and services to remain in high demand, think of hiring a Django developer. But although there are over 24 million developers in the world, hiring a really good one is both difficult and expensive.
In this article, we cover 30 questions you should ask a developer during an interview. Answers to these questions will assist you in deciding whether an applicant is a match for the company.
30 Django interview questions
- What is the meaning and origin of the name Django?
When a couple of software engineers started using Python for crafting applications, they launched a new framework to cope with complex websites. Why “Django”? The framework is named after the famous guitarist. The word “django” is a Romany term and is translated as “I’m awake.”
2. What definition would you give to Django?
Django is a functional framework for crafting the backend of an app. It supports the process with various tools and simplifies it.
3. Is Django a high- or low-level framework?
It is high-level. It was crafted to ensure the fast development of any application. Its use for app development guarantees a design that is realistic and clean.
4. Does Django scale?
Yes, it does. It was designed to take advantage of as much hardware as needed and scales like any other stateless shared-nothing web technology. While working on any project, developers need to verify that the web nodes are independent of caching, the database, and session storage. Only then can they scale the web nodes independently.
Web nodes scale horizontally, so a software engineer can add more of them when they’re needed. The ability to add more web nodes, if necessary, is essential for good scalability.
5. What are the distinctive characteristics of Django, Flask, and Pyramid?
Flask is designed for crafting small apps with mere specifications, whereas Pyramid is created for larger projects and ensures versatility. It gives a set of tools and includes authentication and routing, but external libraries are needed for templating. Django is mainly chosen for larger websites. It offers numerous tools and libraries.
6. What are the framework’s features?
Here’s a list of features provided by Django. They make Django well-suited to quickly developing projects:
- Rapid project processing
- High level of security
- Flexible and suits both small and complex projects
- Libraries and task modules
- Large and supportive community
7. What are the framework’s architectural elements?
The architecture of the framework comprises three elements:
- Tools to alleviate work with data
- A templating system used both by software engineers and non-developers
- A framework to manage connectivity between users and databases and automate difficult parts of complex websites
8. What are the advantages of this framework?
- Rich ecosystem. It comes with numerous third-party apps. They all can be integrated depending on the requirements of the project.
- Maturity. For over a decade, the framework has been going through numerous stages of upgrading. New features have been added and enhanced. There’s also a huge Django community.
- Admin panel. The panel is crafted to assist with managing the app. It’s generated from Python code and simplifies work with an app.
- Plugins. Plugins allow software engineers to add different features to applications and leave enough room for customization.
- Libraries. The set of software libraries comprises prewritten code, scripts, classes, and procedures. Libraries let you easily add functionality.
- ORM. The object-relational mapper allows software engineers to work with data.
9. What are some disadvantages?
- It is too monotonic and uses the routing pattern for specifying URLs
- It cannot enable individual processes to handle multiple requests simultaneously
- It makes the elements of an application tightly-coupled
- It requires the software engineers to deploy web app components at a time
10. What is the MTV architecture?
It is a design pattern that comprises three elements: Model, Template, and View. The Model gives access to data and is in charge of handling the database. The Template is another layer — presentation — that manages the interface. As for the View, it is in charge of the business logic. It also interacts with the Model and the Template.
11. What top websites are built in Django?
The list of top websites built on Django includes Instagram and Pinterest, NASA and Disqus, The Onion and Mahalo, Mozilla Firefox and Bitbucket, The Washington Post, and Eventbrite.
12. What do you know about context?
Whenever a Template is rendered, a developer gives it a context. In Django, it is a dictionary that includes variable names (also called keys) and values of those variables. When a developer renders a Template with context, keys become variables that the developer can access and use.
13. Talk me through setting up a database setup
By default, SQLite is used, so nothing else must be installed to support the database. The setup is done in the DATABASES variable of the setting.py file:
Go to the ENGINE settings and set the type of the database. Additional settings such as NAME, USER, PASSWORD, HOST, and PORT are a must to ensure proper access.
14. What backends does Django support?
There are four of them: PostgreSQL and MySQL, SQLite and Oracle. There are also third-party backends such as ODBC, Microsoft SQL Server, IBM DB2, SAP SQL Anywhere, and Firebird.
15. What are Django Views and what is their purpose?
A View is a function responsible for taking web requests and returning web responses. A function is characterized by the presence of arbitrary logic required for returning responses. The code can live anywhere, but by default, the location is views.py. The View provides the following responses: a 404 error, the HTML content of a page, an XML document, an image, a redirect, or anything else.
16. How can you combine two or more QuerySets in a View?
Concatenating QuerySets into lists is believed to be the easiest approach. Here’s an example of how to do that:
from itertools import chain
result_list = list(chain(model1_list, model2_list, model3_list))
It’s faster to use itertools.chain than to loop each list and add elements one by one. Why? Because the itertools module is written in C and uses less memory.
17. Define static files and explain their uses.
- Сheck if there are static files in installed apps
- Define the URL
- Build the correct URL with a static Template
- Store static files in a relevant folder
18. What are Templates and what are they used for?
Templates are parts of a common approach to generating HTML in a dynamic way. Every Template comprises both static parts and special syntax that shows how the content will be inserted. One or more template engines can be used within a single project. Developers can make use of built-in backends for the Django Template System. In the case of use of some other language, backends are available from third parties.
To load and render the Templates, this framework defines a standard API. Loading means searching for and preprocessing a Template. Rendering means interpolating data based on the context.
19. What are Django cookies and what are they used for?
Other names for cookies are browser/Internet/web cookies. No matter what you call them, they’re mechanisms that assist websites in remembering all kinds of stateful information and recording the browsing activity of a user. The framework, for its part, ensures complete support for anonymous sessions.
20. What’s the session framework?
Sessions are mechanisms for storing and retrieving data. For security purposes, there’s a session framework that handles cookies. It abstracts the cookies (received and sent), saves data on the server side, and helps to bypass “don’t accept cookies” settings.
21. How can you use file-based sessions?
You need to change the SESSION_ENGINE settings in the “django.contrib.sessions.backends.file.”
22. What are loaddata and dumpdata?
Dumpdata is a command to back up both current model instances and the whole database. Its syntax is rather simple. The command ./manage.py dumpdata > db.json will dump the whole database into a db.json file.
The loaddata command (/manage.py loaddata > db.json) allows load dumps (or fixtures) into a database. Its syntax is also simple.
23. What can you tell me about Django translation support and makemessages?
You need to insert a minimum quality of hooks (strings) if a website must be a translatable one. Hooks tell Django that the given text must be interpreted into the language of a user in case there actually is an available interpretation. For the system to know what strings should be translated (interpreted), a developer has to mark these strings. Django provides tools that work extracting (or translating) hooks into files. Makemessages are commands that run over the source tree and pull out all marked hooks.
24. How are styles inherited in Django models?
They are often compared to those in Python, but there are differences to keep in mind. For example, you need to choose whether the parent model should have an individual database table or is just for holding information.
Basically, there are three styles:
- Abstract base classes hold information repeated in all models.
- Multi-table inheritance is for models with individual tables.
- Proxy models are for the modification of the model’s behavior.
25. What is a mixin?
It’s a package of features added to a class when needed. The package is actually “mixed in,” because the process itself implies that the package features are connected to the class features through inheritance mechanisms. This connection provides solutions to common language-related problems.
In Django, these packages are used in class-based views. When a developer doesn’t need a lot of functionality or wants to use only certain features, they can use mixins to inject the needed part of functionality into a class.
26. What is a signal dispatcher?
This framework is featured by a “signal dispatcher” that notifies decoupled apps whenever framework-related actions take place. This feature is useful, especially when separate parts of the code must be informed of the same actions. To ensure proper notification, Django offers signals that are already built into the framework.
27. What are the roles of signals?
Whenever models undergo certain changes, Django handles the situation through signals. Signals require the cooperation of senders (those sending signals) and handlers or receivers (those receiving and processing signals).
28. Talk me through the process of creating a superuser account.
This account is created to ensure access to framework admin site. Assuming that the project folder is located in /opt/bitnami/apps/django/django_projects, start with renaming the folder: cd /opt/bitnami/apps/django/django_projects/PROJECT. Then create a new superuser: python3 manage.py createsuperuser. After this, wait for the prompt, fill in the information, and the setup is completed.
29. What’s a “slug” and how is it used?
The slug is the URL part written in a way that makes it easy to read and explain the contents of the page. Having pretty URLs (by pretty we mean SEO-friendly and readable) is essential. That’s why the framework offers a slugify method for converting any title into a slugfield version.
Let’s say you have a page titled “Top popular movies.” The slugified version would look like “top-popular-movies,” while the complete URL might be “/2019/08/29/16/5-top-popular-movies/.”
30. Tell me a bit about the discrepancy between the Django OneToOneField and ForeignKey.
ForeignKey together with OneToOneField are the two most common types of Django fields. In databases, ForeignKey is used for many-to-one relationships; it requires the on_delete option along with a model’s class. On the other hand, there’s the OneToOneField, which carries out one-to-one relationships and requires only the model’s class.
We hope our guide has provided you with the information you’ve been looking for. If you have questions about what comes before an in-person interview, you’ll find more detailed information in this page on how to hire a Python or Django developer.