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  • Django ORM (三) 查询,删除,更新操作

    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")
    
    

    获取除了 id 为2 的 book
    book = models.Book.objects.exclude(id=2)

    反向查找

    from django.shortcuts import render, HttpResponse
    from app01 import models
    from  app01.models import Book,Author,Publisher
    
    def data_oper(req):
        # 查找 Publish name 是 广东工业出版社 的 书籍
        obj=models.Publisher.objects.filter(name="广东工业出版社")[0]
        print(obj.book_set.all().values("title"))
    
        return HttpResponse("Hello world")
    
    

    def data_oper(req):
        # 查找书籍名为 K8S 的出版社名字
        print(models.Publisher.objects.filter(book__title="K8S").values("name"))
        # 查找出版社名为 广东工业出版社 的书籍名字
        print(models.Book.objects.filter(publisher__name="广东工业出版社").values("title"))
    
        return HttpResponse("Hello world")
    

    from django.shortcuts import render, HttpResponse
    from app01 import models
    from  app01.models import Book,Author,Publisher
    
    def data_oper(req):
        # 查询所有出版社城市为 广州 的书名
       ret = models.Book.objects.filter(publisher__city='广州').values('title')
        print(ret)
    
        # 查询对应操作的sql语句
        print(ret.query)
    
        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")
    
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  • 原文地址:https://www.cnblogs.com/klvchen/p/10894246.html
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