day 81 天 ORM 操作复习总结

# ###############基于对象查询（子查询）##############

一、对多查询

 正向查询

from django.shortcuts import render,HttpResponse
from app01 import models
# Create your views here.

def query(request):
    # ###############基于对象查询（子查询）##############
    # 一对多查询 book-->publish
    #正向查询：
    # 查询python这本书的出版社的email邮箱.
    python_obj = models.Book.objects.filter(title ='python').first()
    print(python_obj.publish.email)
    return HttpResponse(' OK')

　　

# ###############基于对象查询（子查询）##############
                    # 正向查询按字段查询
# 一对多查询 book----------------------->publish
#                  <----------------------
                    #反向查询 book_set.all()

反向查询

反向查询#查询五道口出版社的书籍名称 pub_obj =models.Publish.objects.filter(name ='五道口出版社').last()

 for obj  in pub_obj.book_set.all():
     print(obj.title)

 return HttpResponse(' OK')

二、多对多 查询

            # 按字段查询 正向查询（author.all())
# 多对多  book----------------------> author
            # <----------------------
            # book_set.all()

正向多对多查询

#查询python作者的年龄

python_obj =models.Book.objects.filter(title ='python').first()
    print(python_obj)
    for author in  python_obj.authors.all():
        print(author.name,author.age)

    return HttpResponse('ok')

输出结果

反向多对多 

  #查询 alex出版过的书籍
    alex =models.Author.objects.filter(name ='哪吒').first()
    for book  in alex.book_set.all():
        print(book.title)

    return HttpResponse('ok')

 三 、一对一的关系

author 于authordetail表的关系 。

一对一正向查询

反向查询

查询家在山东的作者名：

###############基于queryset和__查询（join的查询)####################

四 、

正向查询 ： 按字段 

反向查询：按表名 

案例1 . 

#查询python这本书籍的出版社的邮箱

   python_obj = models.Book.objects.filter(title ='python').first()

    print(python_obj.publish.email)

    return HttpResponse(' OK')

　　

案例2.   

 案例3 

两种方法

输出结果：

VIEWS文件 ：

from django.shortcuts import render,HttpResponse
from app01 import models
# Create your views here.

def query(request):
    # ###############基于对象查询（子查询）##############
                        # 正向查询按字段查询
    # 一对多查询 book----------------------->publish
    #                  <----------------------
                        #反向查询 book_set.all()
    # #正向查询：
    #
    # # 查询python这本书的出版社的email邮箱.
    #
    # python_obj = models.Book.objects.filter(title ='python').first()
    # print(python_obj.publish.email)

    #f反向查询 按表明小写_set.all()
   #查询五道口出版社的书籍名称
    # pub_obj =models.Publish.objects.filter(name ='五道口出版社').last()
    # for obj  in pub_obj.book_set.all():
    #     print(obj.title)

            # 按字段查询 正向查询（author.all())
# 多对多  book----------------------> author
            # <----------------------
            # book_set.all()
            #查询python作者的年龄
    # python_obj =models.Book.objects.filter(title ='python').first()
    # print(python_obj)
    # for author in  python_obj.authors.all():
    #     print(author.name,author.age)

  #查询 alex出版过的书籍
    # alex =models.Author.objects.filter(name ='哪吒').first()
    # for book  in alex.book_set.all():
    #     print(book.title)
    #

          # 按字段查询 正向查询（authordetail.all())
    # 多对多  author----------------------> authordetail
                # <----------------------
               # 按表名 author

    #查询 哪吒的电话号码
    nezhao_obj = models.Author.objects.filter(name ='哪吒').first()
    print(nezhao_obj.authorDetail.telephone)

    # 反向查询
    # 查询家在山东的作者名字
    add_obj = models.AuthorDetail.objects.filter(addr ="山东").first()
    print(add_obj.author.name)

    #############################基于queryset和__查询（join的查询)#########################

    #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 )

    #查询清华出版社的书籍名称
    #方法1
    qinghua_obj =models.Publish.objects.filter(name ='清华出版社').values('book__title')
    print(qinghua_obj)
    #方法2
    qinghua_obj=  models.Book.objects.filter(publish__name='清华出版社').values('title')
    print(qinghua_obj)

    #   查询哪吒的手机号
    ret = models.Author.objects.filter(name ='哪吒').values('authorDetail__telephone')
    print(ret)
    return HttpResponse('ok')

    #查询手机号 以 186开头的作者的出版过的书籍名称以及对应的出版社

　　

2018.10.29日整理

from django.db import models

# Create your models here.

class Author(models.Model):
    nid = models.AutoField(primary_key=True)
    name=models.CharField( max_length=)
    age=models.IntegerField()

    # 与AuthorDetail建立一对一的关系
    authorDetail=models.OneToOneField(to="AuthorDetail",on_delete=models.CASCADE)
    def __str__(self):
        return  self.name

class AuthorDetail(models.Model):

    nid = models.AutoField(primary_key=True)
    birthday=models.DateField()
    telephone=models.BigIntegerField()
    addr=models.CharField( max_length=)

    def __str__(self):
        return  self.addr

class Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name=models.CharField( max_length=)
    city=models.CharField( max_length=)
    email=models.EmailField()

    def __str__(self):
        return  self.name

class Book(models.Model):

    nid = models.AutoField(primary_key=True)
    title = models.CharField( max_length=)
    publishDate=models.DateField()
    price=models.DecimalField(max_digits=,decimal_places=)

    # 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',)
    def __str__(self):
        return  self.title

orm查询

from django.shortcuts import render,HttpResponse

# Create your views here.
from .models import *
def index(request):
    #查询沙河出版社所有书籍的名称和价格（一对多）
    ret = Publish.objects.filter(name="沙河出版社").values("book__title","book__price")  #正向查询按字段，反向查询按表名.
    print(ret)
    #打印结果：<QuerySet [{'book__title': 'python入门', 'book__price': Decimal('100.00')}]>
    """
     select book.title,book.price from Publish inner join book on Publish.pk =Book.pulish_id where publish.name ="沙河出版社"
    """
    ret=Book.objects.filter(publish__name="沙河出版社").values("title","price")
    print(ret)
    #打印结果：<QuerySet [{'title': 'python入门', 'price': Decimal('100.00')}]>

    return  HttpResponse("ok ")