数据库模型
from django.db import models# Create your models here.from django.db import models# Create your models here.class Author(models.Model): nid = models.AutoField(primary_key=True) name=models.CharField( max_length=32) age=models.IntegerField() # 与AuthorDetail建立一对一的关系 authorDetail=models.OneToOneField(to="AuthorDetail",on_delete=models.CASCADE)class AuthorDetail(models.Model): nid = models.AutoField(primary_key=True) birthday=models.DateField() telephone=models.BigIntegerField() addr=models.CharField( max_length=64)class Publish(models.Model): nid = models.AutoField(primary_key=True) name=models.CharField( max_length=32) city=models.CharField( max_length=32) email=models.EmailField()class Book(models.Model): nid = models.AutoField(primary_key=True) title = models.CharField( max_length=32) publishDate=models.DateField() price=models.DecimalField(max_digits=5,decimal_places=2) # 与Publish建立一对多的关系,外键字段建立在多的一方 publish=models.ForeignKey(to="Publish",to_field="nid",on_delete=models.CASCADE) # 与Author表建立多对多的关系,ManyToManyField可以建在两个模型中的任意一个，自动创建第三张表 authors=models.ManyToManyField(to='Author',)
查询语句
from django.shortcuts import render,HttpResponse# Create your views here.from app01 import modelsdef query(request): # #####################基于对象查询(子查询)############################## # 按字段（publish） # 一对多 book -----------------> publish # <---------------- # book_set.all() # 正向查询按字段： # 查询python这本书籍的出版社的邮箱 # python=models.Book.objects.filter(title="python").first() # print(python.publish.email) # 反向查询按 表名小写_set.all() # 苹果出版社出版的书籍名称 # publish_obj=models.Publish.objects.filter(name="苹果出版社").first() # for obj in publish_obj.book_set.all(): # print(obj.title) # 按字段（authors.all()） # 多对多 book -----------------------> author # <---------------- # book_set.all() # 查询python作者的年龄 # python = models.Book.objects.filter(title="python").first() # for author in python.authors.all(): # print(author.name ,author.age) # 查询alex出版过的书籍名称 # alex=models.Author.objects.filter(name="alex").first() # for book in alex.book_set.all(): # print(book.title) # 按字段 authorDetail # 多对多 author -----------------------> authordetail # <---------------- # 按表名 author #查询alex的手机号 # alex=models.Author.objects.filter(name='alex').first() # print(alex.authorDetail.telephone) # 查询家在山东的作者名字 # ad_list=models.AuthorDetail.objects.filter(addr="shandong") # # for ad in ad_list: # print(ad.author.name) ''' 对应sql: select publish_id from Book where title="python" select email from Publish where nid = 1 ''' # #####################基于queryset和__查询（join查询）############################ # 正向查询：按字段 反向查询：表名小写 # 查询python这本书籍的出版社的邮箱 # ret=models.Book.objects.filter(title="python").values("publish__email") # print(ret.query) ''' select publish.email from Book left join Publish on book.publish_id=publish.nid where book.title="python" ''' # 苹果出版社出版的书籍名称 # 方式1： ret1=models.Publish.objects.filter(name="苹果出版社").values("book__title") print("111111111====>",ret1.query) #方式2： ret2=models.Book.objects.filter(publish__name="苹果出版社").values("title") print("2222222222====>", ret2.query) #查询alex的手机号 # 方式1： ret=models.Author.objects.filter(name="alex").values("authorDetail__telephone") # 方式2： models.AuthorDetail.objects.filter(author__name="alex").values("telephone") # 查询手机号以151开头的作者出版过的书籍名称以及书籍对应的出版社名称 ret=models.Book.objects.filter(authors__authorDetail__telephone__startswith="151").values('title',"publish__name") print(ret.query) return HttpResponse("OK")