Django模型关系与视图操作详解：增删改查及跨表查询实战

from django.db import models
# Create your models here.
class AuthorDetail(models.Model):
  gf=models.CharField(max_length=32)
  tel=models.CharField(max_length=32)
class Author(models.Model):
  name=models.CharField(max_length=32)
  age=models.IntegerField()
  # 与AuthorDetail建立一对一的关系
  # ad=models.ForeignKey(to="AuthorDetail",to_field="id",on_delete=models.CASCADE,unique=True)
  ad=models.OneToOneField(to="AuthorDetail",to_field="id",on_delete=models.CASCADE,)
class Publish(models.Model):
  name=models.CharField(max_length=32)
  email=models.CharField(max_length=32)
  addr=models.CharField(max_length=32)
class Book(models.Model):
  title=models.CharField(max_length=32,unique=True)
  price=models.DecimalField(max_digits=8,decimal_places=2,null=True)
  pub_date=models.DateField()
  # 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="id",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，自动创建关系表book_authors
  authors=models.ManyToManyField(to="Author")

from django.shortcuts import render,HttpResponse
from app01.models import AuthorDetail,Author,Publish,Book
# Create your views here.
def add(request):
  # 注意：因为author的ad属性是关联authordetail表，必须添加authordetail表，才能添加author表。
  # hong_gf=AuthorDetail.objects.create(gf='小唐',tel=1314)
  # hong=Author.objects.create(name='hong',age='25',ad=hong_gf)
  # print(hong)
  # # publish_id就是Book类的publish属性。它的字段为publish_id
  # book = Book.objects.create(title='西游记', price=100, pub_date="1743-4-12", publish_id=2)
  # print(book.title) # 打印title
  # return HttpResponse('添加成功')
  # xigua = Publish.objects.filter(name="西瓜出版社").first() #model对象
  # book = Book.objects.create(title='三国演义',price=300,pub_date="1643-4-12",publish=xigua)
  # return HttpResponse('添加成功')

  # book = Book.objects.create(title='python',price=122,pub_date="2012-12-12",publish_id=1)
  # xiao = Author.objects.filter(name="xiao").first() #取Author表name为xiao的id
  # zhang = Author.objects.filter(name="zhang").first()
  # print(zhang)
  # book.authors.add(xiao,zhang) # 添加2条数据,接收一个参数，就会产生一条记录
  #
  # return HttpResponse('添加成功')

  # book = Book.objects.create(title='linux', price=155, pub_date="2013-12-12", publish_id=2)
  # author_list=Author.objects.all()
  # book.authors.add(*author_list)
  # return HttpResponse('添加成功')

  #解除绑定关系
  # book = Book.objects.filter(id=3).first() # 先找到这本书
  # xiao = Author.objects.filter(name="xiao").first() # 再找到作者
  # book.authors.remove(xiao) # 解除绑定的关系
  # return HttpResponse('解除绑定成功')

  #清空所有关系对象
  # book = Book.objects.filter(id=4).first()
  # book.authors.clear() # 清理所有关系对象
  # return HttpResponse('清理成功')

  #绑定唯一的作者或者几个作者，放入一个列表中
  book=Book.objects.filter(id=3).first()
  wang=Author.objects.filter(name='wang').first()
  book.authors.set([wang]) #先清空再设置
  return HttpResponse('绑定唯一作者成功')

def add(request):
  book = Book.objects.filter(title="西游记").first() #过滤出记录
  publish_id = book.publish_id #找出书籍对应的出版社id
  publish = Publish.objects.filter(id=publish_id).first() #根据id号在 Publish表中找出出版社名称
  print(publish.name)

def add(request):
　　book = Book.objects.filter(title="西游记").first() #找出Book表中title为 西游记的 记录
　　print(book.publish.name) #书籍.出版社.名称
 

def add(request):
  publish = Publish.objects.filter(name="西瓜出版社").first() # 先找出版社
  ret = Book.objects.filter(publish_id=publish.id).values("title") # 再找书籍
  print(ret)
　　return HttpResponse('ok')

def add(request):
  publish = Publish.objects.filter(name="西瓜出版社").first() # 先找出版社
  ret = publish.book_set.all().values("title") # 再找书籍,过滤title
  print(ret)
  return HttpResponse('ok')

def add(request):
  book = Book.objects.filter(title="python").first() # 先找书籍
  ret = book.authors.all().values("name","age") # 再找作者,过滤name和age
  print(ret)
  return HttpResponse('ok')

def add(request):
  xiao = Author.objects.filter(name="xiao").first() # 先找作者
  ret = xiao.book_set.all().values("title") # 再找书籍,过滤title
  print(ret)
  return HttpResponse('ok')

def add(request):
  xiao = Author.objects.filter(name="xiao").first() # 先找作者
  ret = xiao.ad.gf # 再找女朋友
  print(ret)
  return HttpResponse('ok')

def add(request):
  phone = AuthorDetail.objects.filter(tel="112").first() # 先找号码
  ret = phone.author.name # 再找作者的名字
  print(ret)