Django ORM (三) 查詢，刪除，更新操作

ORM 查詢操作

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):
    # 獲取 book 表 id 為2的價格
    book = models.Book.objects.filter(id=2).values("price")
    print(book)

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

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

    # 以 id 為倒序排列輸出記錄
    author2 = models.Author.objects.order_by("-id")
    print(author2)

    return HttpResponse("Hello world")

獲取除了 id 為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 廣東工業出版社 的 書籍
    obj=models.Publisher.objects.filter(name="廣東工業出版社")[0]
    print(obj.book_set.all().values("title"))

    return HttpResponse("Hello world")

def data_oper(req):
    # 查找書籍名為 K8S 的出版社名字
    print(models.Publisher.objects.filter(book__title="K8S").values("name"))
    # 查找出版社名為 廣東工業出版社 的書籍名字
    print(models.Book.objects.filter(publisher__name="廣東工業出版社").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):
    # 查詢所有出版社城市為 廣州 的書名
   ret = models.Book.objects.filter(publisher__city='廣州').values('title')
    print(ret)

    # 查詢對應操作的sql語句
    print(ret.query)

    return HttpResponse("Hello world")

ORM 刪除操作

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):
    # 多對多的情況下，刪除 book id 為1，author id 大於0的記錄
    book = models.Book.objects.filter(id=2)[0]
    authors = models.Author.objects.filter(id__gt=0)
    book.authors.remove(*authors)

    # 刪除單條記錄，刪除 book 表中 id 為 1 的記錄
    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 為 3 的 name 改為 katy
    author = models.Author.objects.get(id=3)
    author.name = "katy"
    author.save()

    return HttpResponse("Hello world")