Django Backend Developer Interview Questions
Django is a Python-based web framework which allows you to quickly create web application without all of the installation or dependency problems that you normally will find with other frameworks. Django is based on MVT (Model-View-Template) architecture. MVT is a software design pattern for developing a web application.
Templates are the third and most important part of Django’s MVT Structure. A template in Django is basically written in HTML, CSS, and Javascript in a .html file. Django framework efficiently handles and generates dynamic HTML web pages that are visible to the end-user.
Django lets us interact with its database models, i.e. add, delete, modify, and query objects, using a database-abstraction API called ORM(Object Relational Mapper).Django’s Object-Relational Mapping (ORM) system, a fundamental component that bridges the gap between the database and the application’s code.
51. How to get a particular item in the Model?
In Django, you can retrieve a particular item (a specific record or instance) from a model using the model’s manager and a query.
Assuming you have a Django model named YourModel defined in an app named your_app:
- Import the Model: Make sure to import your model in the Python file where you need to retrieve the item.
from your_app.models import YourModel
- Use the Model’s Manager: Every Django model comes with a default manager called objects. You can use this manager to perform queries on the model.
- Perform the Query: Use a query to filter the items based on the criteria you want. For example, if you want to retrieve an item by its primary key (id field), you can use the get method.
*Remember to replace YourModel with the actual name of your model and adjust the query criteria based on the fields of your model that you want to use for retrieval. If you need to retrieve multiple items based on certain conditions, you can use the filter method instead of get.
In Django, select_related and prefetch_related are designed to stop the deluge of database queries that are caused by accessing related objects.
- select_related() “follows” foreign-key relationships, selecting additional related-object data when it executes its query.
- prefetch_related() does a separate lookup for each relationship and does the “joining” in Python.
A QuerySet is a collection of database queries to retrieve data from your database. It represents a set of records from a database table or a result of a database query. Query sets are lazy, meaning they are not evaluated until you explicitly request the data, which makes them highly efficient.
Django Field Choices. According to documentation Field Choices are a sequence consisting itself of iterables of exactly two items (e.g. [(A, B), (A, B) …]) to use as choices for some field.Choices limits the input from the user to the particular values specified in models.py. If choices are given, they’re enforced by model validation and the default form widget will be a select box with these choices instead of the standard text field.
In Django, views are Python functions which take a URL request as parameter and return an HTTP response or throw an exception like 404. Each view needs to be mapped to a corresponding URL pattern. This is done via a Python module called URLConf(URL configuration).
Here’s a sample code for books/urls.py:
from django.contrib import admin
from django.urls import path, include
urlpatterns = [
path('admin/', admin.site.urls),
path('', include('books.urls')),
]
Django Views are one of the vital participants of MVT Structure of Django. As per Django Documentation, A view function is a Python function that takes a Web request and returns a Web response. This response can be the HTML contents of a Web page, or a redirect, or a 404 error, or an XML document, or an image, anything that a web browser can display.
A Django model is the built-in feature that Django uses to create tables, their fields, and various constraints. In short, Django Models is the SQL Database one uses with Django. SQL (Structured Query Language) is complex and involves a lot of different queries for creating, deleting, updating, or any other stuff related to a database.
Example: Below is an example of Django models.
from django.db import models
# Create your models here.
class GeeksModel(models.Model):
title = models.CharField(max_length = 200)
description = models.TextField()
Backend Developer Interview Questions
Backend development involves working on the server side of web applications, where the logic, database interactions, and server management take place. It focuses on handling data, processing requests from clients, and generating appropriate responses.
In this Top Backend Development interview questions, We cover Interview questions from all important topics from basic to advanced such as JavaScript, Node.js, Express.js, SQL, MongoDB, Django, PHP, Java Spring, and API. No matter whether you are a fresher or an experienced professional we have got questions that will enhance your skills and help you shine in your backend development interview.
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