Django Getting Started Guide: An efficient tool to quickly learn Python web programming

Django is an efficient Python web programming framework that provides a complete set of tools and components for rapid development of web applications. This article will introduce you to the basics of Django and how to use it to implement a web application.

1. Introduction to Django

Django is an open source web framework written in Python. It originated from an online news reporting website and was born in 2005. It is designed to facilitate web developers to develop web applications faster and more efficiently. Its goal is to improve developer efficiency, adopting the philosophy of "design specifications are better than code volume", abstracting common problems in web development into high-level concepts, and providing various tools needed to quickly develop web applications. and function.

2. Features of the Django framework

The Django framework has the following main features:

2.1 Efficient Model-View-Controller (MVC) pattern

The Django framework uses the MVC pattern and divides the application into three parts: model, view, and controller. This design approach allows developers to separate the application's logic, data, and user interface. This makes it easy to manage code, improving reusability and maintainability.

2.2 Automated management system

The Django framework has a highly automated management system that can automatically manage data in the back-end database. This allows developers to create, update and query the database without writing any code.

2.3 Built-in ORM framework

Django has a built-in ORM framework that allows developers to use an object-oriented approach instead of using SQL statements to access the database.

2.4 Efficient template system

Django’s template system has the advantages of high efficiency, easy maintenance, and easy expansion. It allows developers to reuse code snippets without duplicating code.

2.5 Built-in user authentication system

Django has a built-in user authentication system that allows web applications to manage and verify user identities. This system can be easily extended and customized to suit specific web applications.

3. Main components of Django

Django is composed of multiple components (or applications) that are reusable and can be used in combination. The following are the main components of Django:

3.1 URL dispatcher (URL dispatcher)

The URL dispatcher maps the requested URL to the corresponding view function.

3.2 Template Engines

The template engine renders the template file into the final HTML page.

3.3 Form Handler

Django’s form handler helps developers handle data entry, data validation and data saving.

3.4 Database Models

Django’s database model is an abstract class used to define the mapping relationship between the data model and the database table.

3.5 Django ORM Framework

Django ORM framework is an object-oriented database access framework that allows developers to write queries, updates and deletes to the database using Python.

4. Django project structure

Django project usually consists of the following parts:

4.1 Django project

Django project is a Container that contains all applications. It is a Python package that contains files for managing web applications.

4.2 Application

The application is an independent component in the Django project. Each application has its own models, views, and controllers, as well as its own URLs and templates.

5. Django Quick Start

The following are the steps to create a Django web application:

5.1 Install Django

First you need to install Django. You can install Django in the terminal using the following command:

sudo pip install Django

5.2 Create a Django project

Use the following command to create a Django project:

django-admin startproject myproject

This command will create a project named Django project for "myproject".

5.3 Create a Django application

Use the following command to create a Django application named "myapp":

python manage.py startapp myapp

This command will create a "myapp" application , and include it in the Django project. Add it to INSTALLED_APPS using the following command:

INSTALLED_APPS = [
    ...
    'myapp',
    ...
]

5.4 Create a model

In Django, a model is an abstract class used in the database ORM. You can use the following command to create a model file named "model.py":

from django.db import models

class MyModel(models.Model):
    name = models.CharField(max_length=50)
    ...

    def __str__(self):
        return self.name

In this model, the "name" field is used to store the name of the model instance. After using the above code, use the following command to create the database:

python manage.py makemigrations
python manage.py migrate

5.5 Create a view

The view is the processing logic between the URL requested by the user and the corresponding data. In this example, we will create a file called "views.py" to process the data:

from django.http import HttpResponse
from myapp.models import MyModel

def index(request):
    items = MyModel.objects.all()

    output = ', '.join([item.name for item in items])
    return HttpResponse(output)

What the above code does is get all the model instances from the database and return them to the client .

5.6 Create URL mapping

In Django, URL mapping is managed by the URL dispatcher. We need to create a file called "urls.py" and add the following code to it:

from django.urls import path
from myapp import views

urlpatterns = [
    path('', views.index, name='index'),
]

5.7 Running the server

Use the following command to start the Django web server locally:

python manage.py runserver

在网页浏览器中输入“http://127.0.0.1:8000/”后，将会看到从数据库中提取的所有名称。

6. 结论

Django是一款高效的Python Web编程框架，它提供了一整套用于快速开发Web应用程序的工具和组件。它支持MVC模式，有一个自动化的管理系统和内置的ORM框架。此外，Django内置的用户身份验证系统和高效的模板系统，进一步提高了Web开发效率。通过这篇文章，您应该对Django的基础知识有所了解，并且可以创建一个Django Web应用程序。

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