ORM初级实战简单的数据库交互

Posted 2020-12-04 topzhao

setting.py中：

  1 """
  2 Django settings for untitled3 project.
  3 
  4 Generated by ‘django-admin startproject‘ using Django 2.0.7.
  5 
  6 For more information on this file, see
  7 https://docs.djangoproject.com/en/2.0/topics/settings/
  8 
  9 For the full list of settings and their values, see
 10 https://docs.djangoproject.com/en/2.0/ref/settings/
 11 """
 12 
 13 import os
 14 
 15 # Build paths inside the project like this: os.path.join(BASE_DIR, ...)
 16 BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 17 
 18 
 19 # Quick-start development settings - unsuitable for production
 20 # See https://docs.djangoproject.com/en/2.0/howto/deployment/checklist/
 21 
 22 # SECURITY WARNING: keep the secret key used in production secret!
 23 SECRET_KEY = ‘3p4)ob=u_tpk_ha+5fs1x8vfn+(s5-92$(05%r04ny9v+dv=qp‘
 24 
 25 # SECURITY WARNING: don‘t run with debug turned on in production!
 26 DEBUG = True
 27 
 28 ALLOWED_HOSTS = []
 29 
 30 
 31 # Application definition
 32 
 33 INSTALLED_APPS = [
 34     ‘django.contrib.admin‘,
 35     ‘django.contrib.auth‘,
 36     ‘django.contrib.contenttypes‘,
 37     ‘django.contrib.sessions‘,
 38     ‘django.contrib.messages‘,
 39     ‘django.contrib.staticfiles‘,
 40     ‘app01‘,
 41 ]
 42 
 43 MIDDLEWARE = [
 44     ‘django.middleware.security.SecurityMiddleware‘,
 45     ‘django.contrib.sessions.middleware.SessionMiddleware‘,
 46     ‘django.middleware.common.CommonMiddleware‘,
 47     #‘django.middleware.csrf.CsrfViewMiddleware‘,
 48     ‘django.contrib.auth.middleware.AuthenticationMiddleware‘,
 49     ‘django.contrib.messages.middleware.MessageMiddleware‘,
 50     ‘django.middleware.clickjacking.XFrameOptionsMiddleware‘,
 51 ]
 52 
 53 ROOT_URLCONF = ‘untitled3.urls‘
 54 
 55 TEMPLATES = [
 56     {
 57         ‘BACKEND‘: ‘django.template.backends.django.DjangoTemplates‘,
 58         ‘DIRS‘: [os.path.join(BASE_DIR, ‘templates‘)]
 59         ,
 60         ‘APP_DIRS‘: True,
 61         ‘OPTIONS‘: {
 62             ‘context_processors‘: [
 63                 ‘django.template.context_processors.debug‘,
 64                 ‘django.template.context_processors.request‘,
 65                 ‘django.contrib.auth.context_processors.auth‘,
 66                 ‘django.contrib.messages.context_processors.messages‘,
 67             ],
 68         },
 69     },
 70 ]
 71 
 72 WSGI_APPLICATION = ‘untitled3.wsgi.application‘
 73 
 74 
 75 # Database
 76 # https://docs.djangoproject.com/en/2.0/ref/settings/#databases
 77 
 78 DATABASES = {
 79     ‘default‘: {
 80         ‘ENGINE‘: ‘django.db.backends.sqlite3‘,
 81         ‘NAME‘: os.path.join(BASE_DIR, ‘db.sqlite3‘),
 82     }
 83 }
 84 
 85 
 86 # Password validation
 87 # https://docs.djangoproject.com/en/2.0/ref/settings/#auth-password-validators
 88 
 89 AUTH_PASSWORD_VALIDATORS = [
 90     {
 91         ‘NAME‘: ‘django.contrib.auth.password_validation.UserAttributeSimilarityValidator‘,
 92     },
 93     {
 94         ‘NAME‘: ‘django.contrib.auth.password_validation.MinimumLengthValidator‘,
 95     },
 96     {
 97         ‘NAME‘: ‘django.contrib.auth.password_validation.CommonPasswordValidator‘,
 98     },
 99     {
100         ‘NAME‘: ‘django.contrib.auth.password_validation.NumericPasswordValidator‘,
101     },
102 ]
103 
104 
105 # Internationalization
106 # https://docs.djangoproject.com/en/2.0/topics/i18n/
107 
108 LANGUAGE_CODE = ‘en-us‘
109 
110 TIME_ZONE = ‘UTC‘
111 
112 USE_I18N = True
113 
114 USE_L10N = True
115 
116 USE_TZ = True
117 
118 
119 # Static files (CSS, javascript, Images)
120 # https://docs.djangoproject.com/en/2.0/howto/static-files/
121 
122 STATIC_URL = ‘/static/‘

View Code

models.py中（数据库创建表结构都在这里）：

 1 from django.db import models
 2 
 3 # Create your models here.
 4 class Business(models.Model):
 5     caption = models.CharField(max_length=32)
 6     code = models.CharField(max_length=32,null=True,default=‘SA‘)#default是设置默认值，null=True是数据库中允许这个字段为空
 7 
 8 class Host(models.Model):
 9     nid = models.AutoField(primary_key=True) #设置主键并自增
10 
11     hostname = models.CharField(max_length=32,db_index=True)#max_length设置字段最大长度
12 
13     ip = models.GenericIPAddressField(protocol=‘ipv4‘,db_index=True)#db_index=True设置为索引
14 
15     port = models.IntegerField()
16 
17     b = models.ForeignKey(to="Business", to_field=‘id‘,on_delete=models.CASCADE)#报错加上了on_delete=models.CASCADE1
18     #设置外键关联Business中的id字段也可写成b = models.ForeignKey(‘Business‘,to_field=‘id‘)

View Code

urls.py中（路由都在这里）：

 1 """untitled3 URL Configuration
 2 
 3 The `urlpatterns` list routes URLs to views. For more information please see:
 4     https://docs.djangoproject.com/en/2.0/topics/http/urls/
 5 Examples:
 6 Function views
 7     1. Add an import:  from my_app import views
 8     2. Add a URL to urlpatterns:  path(‘‘, views.home, name=‘home‘)
 9 Class-based views
10     1. Add an import:  from other_app.views import Home
11     2. Add a URL to urlpatterns:  path(‘‘, Home.as_view(), name=‘home‘)
12 Including another URLconf
13     1. Import the include() function: from django.urls import include, path
14     2. Add a URL to urlpatterns:  path(‘blog/‘, include(‘blog.urls‘))
15 """
16 from django.contrib import admin
17 from django.urls import path
18 from app01 import views
19 from django.conf.urls import url
20 
21 urlpatterns = [
22     path(‘admin/‘, admin.site.urls),
23     url(r‘^business/$‘,views.business),#$是结束符
24 ]

View Code

views.py中(主要业务逻辑都在这里)：

 1 from django.shortcuts import render
 2 from app01 import models
 3 # Create your views here.
 4 def business(request):
 5 
 6 
 7     v1 = models.Business.objects.all()
 8 
 9     #QuerySet
10     #[obj(id,caption,code),obj(id,caption,code),obj(id,caption,code)]  里面的小元素是对象
11 
12     v2 = models.Business.objects.values(‘id‘, ‘caption‘)  # 拿固定列
13     # QuerySet
14     # [{‘id‘:1,‘caption‘:‘xx‘,‘code‘:‘da‘},{....},{.....}]  里面的小元素是字典
15 
16     v3 = models.Business.objects.values_list(‘id‘, ‘code‘)
17     # QuerySet
18     # [(1,开发),(2,运维)]  里面的小元素是字典
19 
20     return render(request,‘business.html‘,{‘v1‘:v1,‘v2‘:v2,‘v3‘:v3})   #注意：一定要加return   第一个参数request是对象不是字符串！不是字符串！不是字符串！

View Code

templates下的XXXX.html中（网页模板都放templates下）：

 1 <!DOCTYPE html>
 2 <html lang="en">
 3 <head>
 4     <meta charset="UTF-8">
 5     <title>Title</title>
 6 </head>
 7 <body>
 8 
 9 <h1> 对象 </h1>
10 <ul>
11     {% for row in v1 %}
12 
13      <li>   {{ row.caption }}-{{ row.code }}    </li>
14 
15     {% endfor %}
16 </ul>
17 
18 <h1> 字典 </h1>
19 
20 <ul>
21     {% for row in v2 %}
22 
23      <li>   {{ row.id }}-{{ row.caption }}    </li>
24 
25     {% endfor %}
26 </ul>
27 
28 
29 <h1> 元组 </h1>
30 
31 <ul>
32     {% for row in v3 %}
33 
34      <li>   {{ row.0}}-{{ row.1 }}    </li>
35 
36     {% endfor %}
37 </ul>
38 
39 </body>
40 </html>

View Code