Django版本：
>>> django.VERSION (4, 1, 0, 'final', 0)
PS：基于前几章的进度进行修改
一、Django ORM 单表实例
#终端执行，创建app1数据模型 django-admin startproject app1
- 修改
app1/app1/settings.py文件
—————————————————————————————————— ALLOWED_HOSTS = ['*'] —————————————————————————————————— INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'app1_model', #添加将要创建的数据模型 ] —————————————————————————————————— #指定数据库 DATABASES = { 'default': { 'ENGINE': 'django.db.backends.mysql', 'NAME': 'app1', 'HOST': '10.10.11.218', 'PORT': '3306', 'USER': 'root', 'PASSWORD': '123456', } } —————————————————————————————————— #修改字符、时区 LANGUAGE_CODE = 'zh-Hans' TIME_ZONE = 'Asia/Shanghai' USE_I18N = True USE_TZ = True ——————————————————————————————————
- 在
app1/app1/__init__.py文件导入mysql模块
import pymysql pymysql.install_as_MySQLdb()
- 在mysql数据库上创建数据库，记得指定数据库编码==（可以使用Nacicat创建，指定utf8和utf8_general_ci的排序规则）==
mysql> create database app1 default charset=utf8; Query OK, 1 row affected (0.00 sec)
创建新模型
- 终端执行，创建模型app1_model
#在第一层app1目录执行 django-admin startapp app1_model
- 修改
app1/app1_model/models.py文件
# -*- coding: utf-8 -*- from django.db import models class Book(models.Model): id = models.AutoField(primary_key=True) #id会自动闯进啊 title = models.CharField(max_length=32) #书籍名称 price = models.DecimalField(max_digits=5,decimal_places=2) #书籍价格 publish = models.CharField(max_length=32) #出版社名称 pub_date = models.DateField() #出版时间
- 终端执行，创建表结构
注意：注意要在manage.py目录下执行，如果执行错的话，可以先把app1_model目录中的migrations子目录删除，然后到正确目录执行
(test) PS F:\django\app1> python .\manage.py migrate #创建表的主结构 Operations to perform: Apply all migrations: admin, auth, contenttypes, sessions Running migrations: Applying contenttypes.0001_initial... OK Applying auth.0001_initial... OK Applying admin.0001_initial... OK Applying admin.0002_logentry_remove_auto_add... OK Applying admin.0003_logentry_add_action_flag_choices... OK Applying contenttypes.0002_remove_content_type_name... OK Applying auth.0002_alter_permission_name_max_length... OK Applying auth.0003_alter_user_email_max_length... OK Applying auth.0004_alter_user_username_opts... OK Applying auth.0005_alter_user_last_login_null... OK Applying auth.0006_require_contenttypes_0002... OK Applying auth.0007_alter_validators_add_error_messages... OK Applying auth.0008_alter_user_username_max_length... OK Applying auth.0009_alter_user_last_name_max_length... OK Applying auth.0010_alter_group_name_max_length... OK Applying auth.0011_update_proxy_permissions... OK Applying auth.0012_alter_user_first_name_max_length... OK Applying sessions.0001_initial... OK (test) PS F:\django\app1> python .\manage.py makemigrations app1_model #提交app1_model的修改 Migrations for 'app1_model': app1_model\migrations\0001_initial.py - Create model Book (test) PS F:\django\app1> python .\manage.py migrate app1_model #创建app1_model的表结构 Operations to perform: Apply all migrations: app1_model Running migrations: Applying app1_model.0001_initial... OK
- 查看mysql数据库，成功创建
mysql> use app1; Database changed mysql> show tables; +----------------------------+ | Tables_in_app1 | +----------------------------+ | app1_model_book | | auth_group | | auth_group_permissions | | auth_permission | | auth_user | | auth_user_groups | | auth_user_user_permissions | | django_admin_log | | django_content_type | | django_migrations | | django_session | +----------------------------+ 11 rows in set (0.00 sec) mysql> show create table app1_model_book; +-----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | app1_model_book | CREATE TABLE `app1_model_book` ( `id` int(11) NOT NULL AUTO_INCREMENT, `title` varchar(32) NOT NULL, `price` decimal(5,2) NOT NULL, `publish` varchar(32) NOT NULL, `pub_date` date NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 | +-----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
- 当前目录结构
二、数据库操作
（1）添加数据
- 配置路由，
app1/app1/urls.py
from django.contrib import admin from django.urls import path from . import views #导入视图 urlpatterns = [ path('admin/', admin.site.urls), path('add_book/',views.add_book), #添加路由 ]
- 数据库添加数据，这里菜鸟教程提供两种方法，分别是
- 模型实例化对象
- 通过ORM提供的objects中的方法
- 这里使用第二种。创建视图文件，
/app1/app1/views.py
# -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): books = models.Book.objects.create(title='九阴神功',price=200,publish='功夫出版社',pub_date='1777-10-10') print(books,type(books)) return HttpResponse('<p>数据添加成功！</p>')
- 现在在终端启动django项目
(test) PS F:\django\app1> python .\manage.py runserver 0.0.0.0:8000 Watching for file changes with StatReloader Performing system checks... System check identified no issues (0 silenced). September 06, 2022 - 15:06:52 Django version 4.1, using settings 'app1.settings' Starting development server at http://0.0.0.0:8000/ Quit the server with CTRL-BREAK.
- 访问
127.0.0.1:8000/add_book
- 查看数据库，发现成功添加
（我这里编码有问题，所以显示乱码了）
- 查看终端输出，可以发现输出的第一个就是之前admin管理平台的那种格式
- 根据上述方法，添加多条数据
（2）查找数据
- 使用
all()方法查询所有数据，返回QuerySet类型数据，类似于列表，里面存放一个个模型类的对象，可以使用索引下标取出模型类的对象，实例：
- 修改app1/app1/views.py # -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): books = models.Book.objects.all() print(books,type(books)) return HttpResponse('<p>查找成功！</p>')
访问测试，查看终端输出，可以发现books输出了一个QuerySet
- 查看具体字段可以使用
for循环
# -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): books = models.Book.objects.all() for i in books: print(i.title) print(i.price) return HttpResponse('<p>查找成功！</p>')
- 访问测试，查看终端输出
filter()
filter()方法用于查询符合条件的数据，返回QuerySet类型数据，实例：
- 修改app1/app1/views.py # -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): #books = models.Book.objects.create(title="九阴神功",price=200,publish="功夫出版社",pub_date="1777-10-10") books = models.Book.objects.filter(pk=3) #pk代表主键，即筛选主键等于3的数据，相当于id=3 print(books) print("------------------------------") books = models.Book.objects.filter(publish="金庸出版社") #筛选publish字段为金庸出版社的数据 print(books,type(books)) return HttpResponse('<p>查找成功！</p>')
- 访问测试，查看终端输出
- 可以添加多个条件
- 修改app1/app1/views.py # -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): #books = models.Book.objects.create(title="九阴神功",price=200,publish="功夫出版社",pub_date="1777-10-10") books = models.Book.objects.filter(pk=3) print(books) print("------------------------------") books = models.Book.objects.filter(publish="金庸出版社",price=200) print(books,type(books)) return HttpResponse('<p>查找成功！</p>')
访问测试
- 使用for循环可以查看数据实例
# -*- coding: utf-8 -*- from django.shortcuts import render,HttpResponse from app1_model import models def add_book(request): #books = models.Book.objects.create(title="九阴神功",price=200,publish="功夫出版社",pub_date="1777-10-10") books = models.Book.objects.filter(pk=3) #print(books) for i in books: print(i.title) print("------------------------------") books = models.Book.objects.filter(publish="金庸出版社",price=200) for i in books: print(i.title) #print(books,type(books)) return HttpResponse('<p>查找成功！</p>')
- 访问测试
