这篇文章给大家分享的是有关django外键model如何互相读取的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
先设定一个关系模型如下:
from django.db import models
class Blog(models.Model):
name = models.CharField(max_length=100)
tagline = models.TextField()
def __str__(self):
return self.name
class Author(models.Model):
name = models.CharField(max_length=50)
email = models.EmailField()
def __str__(self):
return self.name
class Entry(models.Model):
blog = models.ForeignKey(Blog)
headline = models.CharField(max_length=255)
body_text = models.TextField()
authors = models.ManyToManyField(Author)
def __str__(self):
return self.headline
上面的数据关系很明晰,Entry中有Blog和Author的外键,如果要在Entry中读取blog和author的数据很容易:
entry = Entry.objects.all()
for e in entry:
blog = e.blog
author = e.authors
要在Blog和Author中读取Entry也可以:
blog = Blog.objects.all()
entry = blog.entry_set.all()
author = Author.objects.all()
entry = author.entry_set.all()
下面通过entry使blog和author互相读取,比如要知道一个blog的Author只需如下:
blogs = Blog.objects.all()
for blog in blogs:
if blog.name== “我们想要查询的博客的name”
author = blog. entry_set.authors
要查询一个author的所有blog如下:
authors = Author.objects.all()
blogs = []
for author in authors:
if author.name== “我们想要查询的Author的name”
for entry in author.entry_set.all():
blogs.append(entry. blog)
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