Table of Contents
Django is a free and open-source web framework with a high level Python foundation that adheres to the model-view-template (MVT) architectural pattern. It was named after the Django Reinhardt. Currently, Django Software Foundation (DSF), an independent US-based organization founded as a 501(c)(3) non-benefit, is responsible for maintaining the framework.
It was developed in the fall of 2003 by Adrian Holovaty and Simon Willson, online programmers for the Lawrence Journal-World newspaper. started developing applications in Python. It was made available to the general public under a BSD license two years later, in July of 2005. Subsequently, the Django development was taken over by the newly formed Django Software Foundation (DSF) in June 2008.
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Introduction
The MODEL, VIEW, and TEMPLATE structure, or MVT framework, is the foundation of Django’s architecture. Three components make up MVT, an alternative to the MVC framework: Model, View, and Controller.Django’s templates take care of all controller-related duties. Stated differently, the contents of the template are a combination of HTML (HyperText Markup Language) and Django Template Language (DTL).
Python-based Django is an open-source, free web application framework. An assembly of components designed to make development easier is called a framework. In contrast to beginning from scratch, they are grouped together and let you create apps or websites from scratch.
Large volumes of information (such as media files), user interactions, heavy traffic, and complicated features or technologies (like machine learning) are all fantastic reasons to utilize Django for your project. But whether you’re working on a smaller project or intend to expand it up significantly, it’s rather easy. Django is used by several companies of all sizes and goals for this reason.
Why Python Django?
A Python-based programming framework is called Django. This Python coding tool expedites the process and adds capabilities. Django comes with pre-written Python code that is prepared for usage in a project. Django is referred to as a “framework” since it comes with an extensive feature set of classes, libraries, and modules that enable developers to accomplish nearly everything necessary to produce reliable websites and applications.
Because Django is developed in Python, it is built upon the foundation of Python. Your website or application is built on top of Django.
1. Designed with Python for Easy Learning
We are all aware of how basic, easy to understand, and simple to learn Python is. Because of its ease of use and short learning curve, this language is a popular choice for novices learning to program. Students are being taught to code using this language in colleges and institutions. This language is used by both novices and experts in the field of computer science for data science, machine learning, and other related areas.
Python is a very stable language, and Django gains many of its main advantages from it. Python is used to write all of the exception files and codes found in the core Django modules. Thus, if you know how to code, learning Django is also simple.
2. Cross-Platform
Since Django is a portable framework, its code can be executed on a variety of operating systems, such as Windows, Linux, Mac, and PC. This framework’s cross-platform capability enables developers to support every development and production environment. The ORM (object-relational mapper) layer in Django sits between the database and the developer. With just a few lines of code changes, you may use this layer to transfer the entire project to different large databases
3. Huge Community Support and Open Source
A free and open-source framework called Django can be found on Github. Almost 2,000 donors have already signed up, and more are signing up every day. It is maintained by the large developer community, and the developers who use it constantly update the code. To address coding-related problems that developers frequently run into when developing a project, the community also introduces a ton of new libraries.
4. Included Batteries
Because Django is known for having “batteries included,” you can find nearly everything you need to create a complete application. These batteries cover a variety of features, such as display layers, model layers, forms, i18n, middlewares, HTTP libraries, session management support, URL routing, ORM, and Python compatibility. Numerous libraries and tools are available for common use cases in the frameworks. This kind of massive support frees developers from having to reinvent the wheel every time, allowing them to concentrate on what really matters.
5. Safety and Security
One of the best things about Django is that it allows you to design and deliver applications more quickly without sacrificing their security. In this framework, security protections are activated by default. Some popular security vulnerabilities, including clickjacking, request forgery, cross-site scripting, and SQL injection, are guarded against by its built-in defense. New security patches are frequently released by Django, which also promptly fixes security flaws and notifies other frameworks.
6. Integrated Admin User Interface
It takes a lot of effort to construct the admin panel on your own in the majority of frameworks. With every app you develop, Django provides an automatic, feature-rich web interface. The well-organized admin area enables developers to add, edit, and remove users as well as any other app-specific database objects. Using third-party apps and wrappers, you can add a dashboard and alter the admin panel user experience to suit your needs.
7. Object-relational mapper, or ORM
An ORM that works with many databases is provided by Django. In essence, ORM is a package that facilitates database interaction and enables developers to seamlessly move data from databases (such MySQL and PostgreSQL) to objects. Working with numerous databases at once is possible.
Some technologies, like Eloquent, greenDAO, Yii AR, etc., are quite good at handling basic queries; nonetheless, you will eventually have to write the raw queries if the ORM is unable to handle the use case. With Django, this is not the case. It is expertly constructed and responds quickly to database requests.
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Advanced Django interview Questions
Q. Why isn’t permanent redirection a wise choice?
Answer: When you don’t want to send users to the outdated URLs, you should only utilize permanent redirection. The browser caches the response for permanent redirections, thus attempting to redirect to somewhere else will result in problems. The same page will load if your user wishes to go to a different one because this is a browser-side activity
Q. What is meant by mixin?
Q. Define Django Field Class?
Answer:
- The Field will refers to an abstract class that will represents a column in the database table.
- RegisterLookupMixin is the parent class of the Field class. Using get_prep_value() and the from_db_value() function, Django maps Python types to the database and vice versa. These fields are used to generate database tables (db_types()). Fields are therefore essential components of various Django APIs, including models and querysets.
Q. Differentiate between the term Django OneToOneField and ForeignKey Field?
Q. How may a View be made up of numerous QuerySets?
from the import chain of itertools
result_list = list(chain(modelA_list, modelB_list, modelC_list))Q. How can I access a specific item in the model?
ModelName.objects.get(id=”Object”)Note: get() will throw a DoesNotExist exception if the query returns no results. if the provided get() query returns more than one item matching. When this occurs, MultipleObjectsReturned—an attribute of the model class itself—will be raised.
Q. How can the SQL query be extracted from the queryset?
print(queryset.query)Q. In what ways might the Django admin interface’s functionality be altered?
Answer: The functionality of the Django admin interface can be tailored in a number of ways. Using the js argument, you can add JavaScript modules on top of an add/change form that Django generates automatically. This argument essentially consists of a list of URLs pointing to the JavaScript modules that you need to include in your project.
Q. Describe the Q objects in the Django ORM?
from django.db import models
from django.db.models import Q
>> objects = Models.objects.get(
Q x(tag__startswith='HumanSense'),
Q(category=’Nose’) | Q(category=’Ears’)
)
```Query Executed
SELECT * FROM Model WHERE tag LIKE ‘HumanSense%’ AND (category=’Nose’ OR category=’Ears’)
```Q. Explain Django Response lifecycle?
- First of the Django settings.py file is loaded which also contain various middleware classes (
MIDDLEWARES) - The middlewares are also executed in the order in which they are mentioned in the
MIDDLEWAREST - From here on the request is now moved to the URL Router, who simply gets the URL path from the request and tries to map with our given URL paths in the urls.py.
- As soon as it has mapped, it will call the equivalent view function, from where an equivalent response is generated
- The response also passes through the response middlewares and send back to the client/browser.
Q. What are the Django caching strategies?
Answer: The practice of caching involves first processing the output results and then storing them so that, the next time the same results are fetched, they can be accessed more quickly and with less resource usage by using the previously cached results rather than requiring additional processing. Dynamic web pages can be stored in Django’s strong cache system, saving them from having to be reevaluated for every request.
- The easiest to set up and one that caches your entire website is the per-site cache.
- per-view cache: The per-view cache allows you to cache certain views.
- By using template fragment caching, you can only cache a subset of a template.
- low-level cache API: It can use the low-level cache API to manually set, retrieve, and maintain certain objects in the cache.
Q. List the Django exception classes that are available.
Answer: An exception is a unique instance that throws off a program. To handle this situation, Django provides its own exception classes in addition to supporting the basic Python exceptions. Below is a list of some of the exception classes:
- MultipleObjectsReturned: The query raises this error if only one item is expected but multiple items are returned.
- ViewDoesNotExist: Django.URLs raises this exception in the event that a requested view is not available.
- PermissionDenied: This error occurs when a user is not authorized to carry out the requested action.
- SuspiciousOperation: When a single item is anticipated but multiple items are returned, the query raises this error.
- ValidationError: This error occurs when a form’s or model field’s data validation is unsuccessful.
- When the requested field is not present, the error message FieldDoesNotExist is raised.
- The basic class for DoesNotExist exceptions is called ObjectDoesNotExist.
- When models are attempted to be used prior to the app loading process, the error AppRegistryNotReady is raised.
- EmptyResultSet: This exception is raised when a query returns no results.
Q. What is NoSQL, and is it supported by Django?
Answer: Another name for NoSql is a non-relational database, which instead of storing data in a tabular format, does so in a way that is optimized for the particular needs of the data type being saved. Key-value stores, graph databases, wide column databases, and pure documented databases are some of the several kinds of NoSQL databases.
No, CouchDB, Redis, Neo4j, MongoDB, and other no-SQL databases are not officially supported by Django.
Q. Which Django model inheritance styles are there?
Answer: Three inheritance types are supported by Django. They’re
- Base classes that are abstract
- Multi-table proxy models for inheritance
Q. Which databases does Django support?
Answer: Django supports the following databases: MySQL, PostgreSQL, Oracle, and SQLite (Inbuild). Additionally, Django leverages a few third-party packages, such as Firebird, SAP SQL Anywhere, IBM DB2, and Microsoft SQL Server, to manage databases. CouchDB, Redis, Neo4j, MongoDB, and other no-SQL databases are not officially supported by Django.
Q. Django Rest Framework: What Is It?
Answer: An HTTP-based standard for listing, creating, editing, and removing data from your server is called the REST Framework. Built on top of the Django web framework, the DRF (Django REST Framework) is a robust and adaptable toolkit that makes creating REST interfaces easier by lowering the amount of code needed. The REST Framework has various benefits, such as:
- Web-browsable API with great developer usability.
- Auth1 and auth2 packages are included in the authentication policy.
- Both ORM and non-ORM data sources are supported.
- It has excellent community support and a plenty of documentation.
Q. Describe the Django Response lifecycle.
Answer: Whenever a client sends a request to a server, the request and response objects are used by the system to transport information back and forth between the client and server. This is the responsibility of the Django Response lifecycle. The web is used to transfer these request/response objects, together with request metadata like pictures, HTML, CSS, and javascript. The HttpRequest is passed as the first argument to the view method by Django, which loads and displays these data for the user. Every view is accountable for providing a HttpResponse object.
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Q. How do the Model’s filter items work?
Answer: We utilize a QuerySet to filter objects that are present in our database. It is a list of things constructed from a database collection of data. By enabling us to select and arrange the data, QuerySet facilitates our job and makes it simpler for us to obtain the necessary information. The help filter() method lets us retrieve only the rows that match the search term, so we can use it to filter our data.
Q. What distinguishes Django’s TextField from CharField?
Answer:
- A database field called TextField is used to hold large volumes of text. Data, documents, and other things can be stored. For holding small text, like first and last names, use CharField. To test if it functions, let’s create a new instance of the TextField we just created.
- A string field for little to huge strings is called CharField. First names, last names, and other short strings are typically stored in it. Larger text is stored using TextField.
Q. Describe the settings.py file in brief.
Answer: As its name suggests, it is the primary configuration file for the Django file. This file contains a dictionary or list containing all the information related to the Django project, such as databases, middlewares, backend engines, templating engines, installed applications, configurations for main URLs and static file URLs, allowed hosts, servers, and security keys. The settings.py file is run when Django files are started, and then the necessary databases and engines are loaded in order to quickly fulfill the request.
Q. How do Django cookies work?
Answer: A cookie is a little data file that is kept in the browser of the client. Django offers built-in ways to utilize the set_cookie() function to set a cookie and the get() method to retrieve the cookie in order to set and acquire cookies. We can apply the request as well.For cookie values, use the COOKIES[‘key’] array.
Q. How can you find out what version of Django is installed on your computer?
Answer: Put the following command into the command prompt after opening it.
- django –version py -m
Q. Why is the Django framework referred to as loosely coupled?
Answer: Django’s MTV architecture has earned it the reputation of being a loosely coupled framework. As an MVC variation, Django’s design benefits from MTV, which completely isolates server code from the client’s hardware. Models and views reside on the client computer, and templates are only given back to the client. The architectural components are all unique from one another.
Q. Describe the Django Security framework.
Answer: Any website design must take user data security into consideration. Adequate security against several common threats is offered by Django. The following are the security aspects of Django:
- defense against cross-site scripting (XSS)
- safeguard against SQL injection
- Protection against cross-site request forgeries (CSRF)
- Enforcing HTTPS and SSL
- Security of sessions
- protection against clickjacking
- Validation of host headers
Q. Describe Django user authentication.
Answer: By default, Django’s authentication system is set up to manage entities such as users, groups, permissions, and so on. User objects are the primary components of the authentication system. Users are not only authorized but also authenticated by it. To enable more user authentication, we have other options besides using the default method, such as utilizing a range of web apps. The following are the default system objects:
- Users
- Authorizations
- Teams
- System for Hashing Passwords
- Validation of Forms
Q. What does the function “Django.shortcuts.render” do?
Answer: When a view function returns an HTML page as a HttpResponse rather than a simple string, we require the render function. The render function can be used to pass a data dictionary and a template quickly. This function uses a templating engine to mix templates with a data dictionary. Ultimately, render() returns a HttpResponse with the model data and the generated text.
- The syntax is render(request, template_name, using=None, status=None, context=None, and content_type=None).
Q. In Django, what is a context?
Answer: A context in Django is a dictionary where the values correspond to the values of the variables and the keys represent the names of the variables. The template receives this dictionary or context and uses the variables to produce the dynamic content at the end. Specifically, {{ var1 }} would be changed to 11 and {{ var2 }} to 12 in your template when you send this context to the template render method.
Q. What does Django’s serialization mean?
Answer: The Django REST Framework’s serializers are in charge of converting objects into data types that front-end frameworks and javascript can comprehend. Serializers provide deserialization, which permits parsed data to be converted back into complicated types, in addition to validating the incoming data.
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