表結構：

from django.db import models


class Book(models.Model):
    name = models.CharField(max_length=32)
    price = models.IntegerField()
    pub_date = models.DateField()
    publish = models.ForeignKey("Publish")

class Publish(models.Model):
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)
 

外來鍵為publish

表內容：

方法一：

正向查詢

是通過子表book物件取得外來鍵pub_id的相關聯的publish物件 然後通過屬性查詢這個publish的各種資訊

from django.shortcuts import render
from .models import Book
from .models import Publish
# Create your views here.
def index(req):
    book_obj = Book.objects.get(name="python")
    pub_obj = book_obj.publish
    print(pub_obj.name)
    return render(req,"index.html")
 

一號出版社

方法二：

反向查詢

是通過查詢主表publish的物件查詢相關聯的書籍

from django.shortcuts import render
from .models import Book
from .models import Publish
# Create your views here.
def index(req):
    pub_obj = Publish.objects.filter(name="一號出版社")[0]
    books = pub_obj.book_set.all()
    for book in books:
        print(book.publish.name)
    return render(req,"index.html")
 

一號出版社
一號出版社

方法三：

先通過外來鍵名字publish查詢publish物件 找到後通過publish的name欄位進行篩選

from django.shortcuts import render,HttpResponse
from .models import Book
from .models import Publish
# Create your views here.
def index(req):
    ret = Book.objects.filter(publish__name="二號出版社").values("name","price")
    #查詢記錄（filter values 雙下劃線__）
    print(ret)
    return render(req,"index.html")

<QuerySet [{'name': 'java', 'price': 22}, {'name': 'linux運維', 'price': 55}, {'name': 'linux運維2', 'price': 66}]>

查詢書名為python的出版社名字

---------雙下劃線用在values中，切記要加引號

from django.shortcuts import render,HttpResponse
from .models import Book
from .models import Publish
# Create your views here.
def index(req):
    ret = Book.objects.filter(name="python").values("publish__name")
    #查詢記錄（filter values 雙下劃線__）
    print(ret)
    return render(req,"index.html")

<QuerySet [{'publish__name': '一號出版社'}]>