Django database (SQLite) basic introductory tutorial

Catalog

1： Create a project

2: establish blog application

3： Database operation  

4. stay blog_demo Add data to table ：

summary

1： Create a project django-admin startproject mysite

After creation , The structure of the project catalogue is as follows ：

manage.py ----- Django Tools in the project , It allows you to call django shell And database, etc .

settings.py ---- Contains the default settings for the project , Include database information , Debug flags and other working variables .

urls.py ----- Responsible for the URL Schema mapping to application .

2: establish blog application python manage.py startapp blog

After completion , A... Will be generated in the project blog Folder  

3： Database operation  

Initialize database ：

python  Bring their own SQLite database ,Django Support various mainstream databases , Here we first use SQLite.

If you use other databases, please use settings.py Set in file . The default configuration of the database is ：

DATABASES = { 'default': { 'ENGINE': 'django.db.backends.sqlite3', 'NAME': os.path.join(BASE_DIR, 'db.sqlite3'), }}

  Use the default data configuration to initialize the database ：

After command execution , Some data tables will be generated ：

 Django I have a WEB backstage , Create below WEB Background user name and password ：

python manage.py createsuperuser

Be careful ️： The password cannot be similar to the user name , Passwords cannot be pure numbers .

  Next, let's use the account and password created above to log in to the background . To log in to the background , Must be in settings.py File will be created above APP That is to say blog added ：

INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'blog',]

Note that there must be a comma after it ！

start-up django Containers ：

python manage.py runserver

Default WEB The address is http://127.0.0.1, Port is 8000, Use this address and port to access the home page ：

  Next visit django The background of ：http://127.0.0.1/admin

Create a UseInfo surface , And create fields ：

Now let's open up blog In the catalog models.py file , This is what we define blog Where data structures . open mysite/blog/models.py  File modification ：

from django.db import models# Create your models here.class Demo(models.Model): car_num = models.CharField(max_length=32) park_name = models.CharField(max_length=32) jinru_Date = models.CharField(max_length=32) chuqu_Date = models.CharField(max_length=32) time = models.CharField(max_length=32)

Command line execution ：

python manage.py makemigrationspython manage.py migrate

As can be seen from the above figure ,Django By default, the APP Named data table prefix , Take the class name as the data table name ！

The fields created are shown in the following figure ：

4. stay blog_demo Add data to table ：

Django Is in views.py In file , By importing models.py Documents come Create data Of ：

from django.shortcuts import render# Create your views here.from blog import models # Import blog modular from django.shortcuts import HttpResponsedef db_handle(request): # Add data models.Demo.objects.create(car_num=' shan E-BV886', park_name=' Hospital of traditional Chinese medicine ', jinru_Date='2022-02-05', chuqu_Date='2022-02-06', time='1') return HttpResponse('OK')

  Now let's configure the route , So that the browser can access views.py file ：

from blog import viewsurlpatterns = [ path('admin/', admin.site.urls), path(r'db_handle', views.db_handle),]

  Let's visit http://127.0.0.1/db_handle

Check whether the database is created successfully ：

  Above is Create table data , You can also create table data in the format of a dictionary ：

def db_handle(request): dic = {car_num=' shan E-BV886', park_name=' Hospital of traditional Chinese medicine ', jinru_Date='2022-02-05',chuqu_Date='2022-02-06', time='1'} models.Demo.objects.create(**dic) return HttpResponse('OK')

Delete table data ：

views.py The documents are as follows ：

def db_handle(request): # Delete table data models.Demo.objects.filter(id=1).delete() return HttpResponse('OK')

  The operation method is the same as above , Execute it once in the browser , In the data id=1 The data of is deleted ：

Modify table data ： 

def db_handle(request): # Modify table data models.Demo.objects.filter(id=2).update(time=18) return HttpResponse('OK')

Data query ：

In order to display the queried data more intuitively , Here we will use Django The template function of , Let the queried data in WEB Displayed in the browser

stay templates Create a new one in the directory t1.html The file of , The contents are as follows ：

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Django Operating the database </title> <link type="text/css" href="/static/base.css" rel="external nofollow" rel="external nofollow" rel="stylesheet" /></head><body> <table border="1"> <tr> <th> license plate number </th> <th> Parking lot name </th> <th> Admission time </th> <th> Playing time </th> <th> Parking Duration </th> </tr> {% for item in li %} <tr> <td>{{ item.car_num }}</td> <td>{{ item.park_name }}</td> <td>{{ item.jinru_Date }}</td> <td>{{ item.chuqu_Date }}</td> <td>{{ item.time }}</td> </tr> {% endfor %}</body></html>

views.py File query data , And specify the template file to call , The contents are as follows ：

def db_handle(request): user_list_obj = models.Demo.objects.all() return render(request, 't1.html', {'li': user_list_obj})

Be careful ： Because this is under the project templates The template created under the directory , Not in blog Templates created in the application , above views.py Invoked in file t1.html Templates , When it runs, it will appear that it cannot be found t1.html Template error , In order to find mysite/templates Under the template file , We still need to settings.py Path of file configuration template ：

TEMPLATES = [ { 'BACKEND': 'django.template.backends.django.DjangoTemplates', 'DIRS': [os.path.join(BASE_DIR, 'templates')], # Configure template path 'APP_DIRS': True, 'OPTIONS': { 'context_processors': [ 'django.template.context_processors.debug', 'django.template.context_processors.request', 'django.contrib.auth.context_processors.auth', 'django.contrib.messages.context_processors.messages', ], }, },]

Now you can view it in the browser ：

introduce JS,CSS Etc. static files ：

stay mysite Create a new one in the directory static Catalog , take JS,CSS Files are placed in this directory ！ And in settings.py The document specifies static Catalog ：

STATIC_URL = '/static/'STATICFILES_DIRS = ( os.path.join(BASE_DIR, 'static'),)

Form submission data ：

stay Django To be used in post Submit form by , Need to be in settings.py Comment out the following line in the configuration file ：

# 'django.middleware.csrf.CsrfViewMiddleware',

Submit Form （ It's still used here t1.html）：

<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Django Operating the database </title> <link type="text/css" href="/static/base.css" rel="external nofollow" rel="external nofollow" rel="stylesheet" /></head><body> <table border="1"> <tr> <th> license plate number </th> <th> Parking lot name </th> <th> Admission time </th> <th> Playing time </th> <th> Parking Duration </th> </tr> {% for item in li %} <tr> <td>{{ item.car_num }}</td> <td>{{ item.park_name }}</td> <td>{{ item.jinru_Date }}</td> <td>{{ item.chuqu_Date }}</td> <td>{{ item.time }}</td> </tr> {% endfor %} </table> <form action="/db_handle" method="post"> <p><input name="car_num" /></p> <p><input name="park_name" /></p> <p><input name="jinru_Date" /></p> <p><input name="chuqu_Date" /></p> <p><input name="time" /></p> <p><input type="submit" value="submit" /></p> </form></body></html>

Write to database （views.py）：

def db_handle(request): if request.method == "POST": models.Demo.objects.create(car_num=request.POST['car_num'],park_name=request.POST['park_name'],jinru_Date=request.POST['jinru_Date'],chuqu_Date=request.POST['chuqu_Date'],time=request.POST['time']) user_list_obj = models.Demo.objects.all() return render(request, 't1.html', {'li': user_list_obj})

After submitting the data , Here's the picture ：

summary

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