ORM 查询操作

修改 views.py 文件

from django.shortcuts import render, HttpResponse
from app01 import models
from  app01.models import Book,Author,Publisher

def data_oper(req):
    # 获取 book 表 id 为2的价格
    book = models.Book.objects.filter(id=2).values("price")
    print(book)

    # 获取 author 表 id 为 1 的名字
    authors = models.Author.objects.filter(id=1)[0]
    print(authors)

    # 获取 author 表 id 为 3 名字
    author1 = models.Author.objects.get(id=3)
    print(author1)

    # 以 id 为倒序排列输出记录
    author2 = models.Author.objects.order_by("-id")
    print(author2)

    return HttpResponse("Hello world")

ORM 删除操作

修改 views.py 文件

from django.shortcuts import render, HttpResponse
from app01 import models
from  app01.models import Book,Author,Publisher

def data_oper(req):
    # 多对多的情况下，删除 book id 为1，author id 大于0的记录
    book = models.Book.objects.filter(id=2)[0]
    authors = models.Author.objects.filter(id__gt=0)
    book.authors.remove(*authors)

    # 删除单条记录，删除 book 表中 id 为 1 的记录
    models.Book.objects.filter(id=1).delete()



    return HttpResponse("Hello world")

ORM 更新操作

修改 views.py 文件

from django.shortcuts import render, HttpResponse
from app01 import models
from  app01.models import Book,Author,Publisher

def data_oper(req):
    # 把 author id 为 3 的 name 改为 katy
    author = models.Author.objects.get(id=3)
    author.name = "katy"
    author.save()

    return HttpResponse("Hello world")