Basic knowledge of Django

Keywords: Python Django Database MySQL Pycharm

I. Installation and Use

Download and install
- Command line: pip3 install django==1.11.21
- pycharm
Create a project
- Command line:
  - Find a folder to store project files and open the terminal:
  - Django-admin start project project project name
  - Project catalogue
- pycahrm
start-up
- command line
  - Switch to manage.py under the project's root directory
  - python36 manage.py runserver - 127.0.0.1:80`
  - python36 manage.py runserver 80-127.0.0.1:80
  - python36 manage.py runserver 0.0.0.0:80-0.0.0.0:80
- pycharm: point green triangle startup configurable

Simple use

Example: Return the HTML specified file

# stay urls.py in
# Import
from django.shortcuts import HttpResponse,render

# function
def index(request):
    # return HttpResponse('index')
    return render(request,'index.html')

# url Correspondence of sum function
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^index/', index),
]

II. Static Documents

To configure

Settings in settings.py

STATIC_URL = '/static/'          # alias
STATICFILES_DIRS = [            # Set file paths, you can set multiple
    os.path.join(BASE_DIR, 'static1'),
    os.path.join(BASE_DIR, 'static'),
    os.path.join(BASE_DIR, 'static2'),
]

Use
- Add an alias before the path: / static/
- Multiple file paths, using the same alias, are not file names
- If the pathname after the alias is the same, look it up in the order of the STATICFILES_DIRS list
```
<link rel="stylesheet" href="/static/css/login.css">         {# Alias Beginning #} 
```

3. Simple login examples

Notes on form submission data:
- Submit address: action = ", request way: method="post"
- All input boxes have name attributes, such as name="username"
- There is an input box type="submit" or a button
Submit post requests, because there is a csrf check in Django, all requests will go wrong
- Solution: Annotate'django.middleware.csrf.CsrfViewMiddleware'of MIDDLEWARE in settings

redirect

Import: from django.shortcuts import redirect

Usage

# Use in functions,for example
return redirect('/index/')      # Parameter: Path url
# Note: The preceding must be added/，Representatives from url Root splicing, otherwise it will be in the present url Stitching at the back

from django.shortcuts import HttpResponse, render, redirect

def index(request):
    # return HttpResponse('index')
    return render(request, 'index.html')

def login(request):
    if request.method == 'POST':
        # Obtain form Books submitted on forms
        username = request.POST['username']
        password = request.POST['password']
        # Verify username and password
        if models.User.objects.filter(username=username,password=password):
            # Verify successful jump to index page
            # return redirect('https://www.baidu.com/')
            return redirect('/index/')
        # Unsuccessful re-login
    return render(request, 'login.html')

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^index/', views.index),
    url(r'^login/', views.login),
]

Example

IV. app

Create app
- Command line: Python management.py startapp app name
- pycharm: tools - > run management. py task - > input command: startapp app name

Set it in settings.py, for example: app is named app01

INSTALLED_APPS = [
    ...
    'app01',
    'app01.apps.App01Config',       # Recommended Writing
]

Files in app
- migrations: Storing migration files
- admin.py: Background management tool provided by Django
- app.py: Related to app information
- models.py: Contents related to ORM
- views.py: View, function-writing

5. Using MySQL Process

Create a MySQL database: create database day53;

In settings.py, Django connects to MySQL database:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',      # engine 
        'NAME': 'day53',                         # Database name
        'HOST': '127.0.0.1',                     # ip address
        'PORT':3306,                            # port
        'USER':'root',                          # user
        'PASSWORD':'123'                        # Password
    }
}

Write in the init file in the same level directory as settings,py:
```
import pymysql
pymysql.install_as_MySQLdb()
```

Create tables (write classes in models.py under app):

from django.db import models

class User(models.Model):
    username = models.CharField(max_length=32)       # username varchar(32)
    password = models.CharField(max_length=32)       # username varchar(32)

Execute database migration commands:
- Python management.py makemigrations: detect model.py under each registered app and record changes to model
- Python management.py migrate: Synchronize changes recorded in the database

VI. MVC and MTV

MVC
- M: model Model Model - Dealing with Database
- V: view View - HTML
- C: controller Controller - Business Logic for Scheduling Transfer Instructions
MTV:
- M: model Model ORM - Dealing with Database
- T: tempalte Template - HTML
- V: view View - Functional Business Logic
djando is MTV mode

Programmer Group

Basic knowledge of Django

I. Installation and Use

II. Static Documents

3. Simple login examples

IV. app

5. Using MySQL Process

VI. MVC and MTV

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