Introduction to Django framework and creating projects

1. Preliminary preparation

Open the command line of anaconda and activate the environment command in windows

venv\Scripts\activate

To close, enter deactivate

Install the Django web framework

pip install Django

Create a project from the command line

django-admin startproject blog

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manage.py: the entry point for Django program execution
init.py : an empty file, telling Python that this directory should be considered as a Python package
settings.py: Django's overall configuration file, which can configure App, database, middleware, etc.

Go to the blog directory and execute the project
manage.py is the entry point for Django program execution

python manage.py runserver

At this time, the server is connected.

2. Create an application

Django comes with tools that can generate the corresponding basic directory structure

Create an application article. In a project, the application is usually used to complete the tasks of different modules. A project can contain multiple applications. In Django, each application is a python package.

python manager.py startapp article

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admin.py: configure the file of Django management background
model.py: create the file of database data model object

After the article is created, it will not take effect immediately, you need to activate the application in blogs/settings.py, the code is as follows:

3. Data model format

Add data models to the application, mainly in articles/models.pyfile, create the corresponding class

from django.db import models  # 引入django.db.models模块


class User(models.Model):
    """
    User模型类，数据模型应该继承于models.Model或其子类
    """
    id = models.IntegerField(primary_key=True)  # 主键
    username = models.CharField(max_length=30)  # 用户名，字符串类型
    email = models.CharField(max_length=30)     # 邮箱，字符串类型

class Article(models.Model):
    """
    Article模型类，数据模型应该继承于models.Model或其子类
    """
    id = models.IntegerField(primary_key=True)  # 主键，IntegerField 整数值字段
    title = models.CharField(max_length=120)    # 标题，字符串类型
    content = models.TextField()                # 内容，文本类型
    publish_date = models.DateTimeField()       # 出版时间，日期时间类型
    user = models.ForeignKey(User, on_delete=models.CASCADE) # 设置外键

It contains the corresponding field types.

Perform a database migration, changing the default SQLite database to the more popular MySQL database.

DATABASES = {
    
    
    "default": {
    
    
        "ENGINE": "django.db.backends.mysql",
        "NAME":'mrsoft',#修改为你的数据库名称
        "USER":'ROOT',#修改为你的数据库用户名
        'PASSWORD':'ROOT'#修改为你的数据库密码
    }
}

Connect to your database in terminal

mysql -u root -p

Follow the prompts to enter the user name and password, and create the database after the connection is successful

create database mrsoft default character set utf8;

Install the MySQL database driver PyMySQL, the command is as follows:

pip install pymysql

Then add the following code at the beginning of the __init__.py file:

import pymysql
pymysql.version_info = (1,3,13,"final",0)
pymysql.install_as_MySQLdb()

Then execute the command to create the data table:

python manage.py makemigrations#生成迁移文件

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The migration file is generated successfully.
You may encounter such a problem in the middle: RuntimeError: 'cryptography' package is required for sha256_password or caching_sha2_password auth methods

pip3 install cryptography -i https://pypi.tuna.tsinghua.edu.cn/simple#清华大学源

Just install it.