如何在Django中建立School与Director两个模型的关联？

原代码存在的问题 #

• Director模型的school字段使用CharField无法实现关联，需改用Django的关联字段
• 模型类名school未遵循大驼峰命名规范（应改为School）
• ForeignKey缺少必填的on_delete参数
• related_name包含空格，不符合Django语法要求
• IntegerField和BooleanField不需要max_length参数

方案一：一对一关联（推荐，符合常规业务场景） #

一个学校对应一个校长、一个校长仅负责一所学校，用OneToOneField实现双向关联最合理。

from django.db import models


class Director(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    first_name = models.CharField(max_length=50, verbose_name='Name')
    last_name = models.CharField(max_length=50, verbose_name='Surname')
    # 用OneToOneField关联School，指定级联删除策略
    school = models.OneToOneField('School', on_delete=models.CASCADE, related_name='director', verbose_name='所属学校')
    photo = models.ImageField(upload_to="uploads/img/", max_length=10000, verbose_name='photo')
    birthday = models.DateField(verbose_name='birthday')

    # 自定义属性返回校长全名
    @property
    def full_name(self):
        return f"{self.first_name} {self.last_name}"

    def __str__(self):
        return self.full_name


class School(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    name = models.CharField(max_length=50, verbose_name='name')
    capacity = models.IntegerField(verbose_name='capacity')
    registration_is = models.BooleanField(verbose_name='Registration')

    def __str__(self):
        return self.name

使用示例 #

• 获取学校对应的校长全名：school.director.full_name
• 获取校长对应的学校名称：director.school.name

方案二：一对多关联（适用于一个校长管理多所学校的场景） #

如果业务允许一位校长负责多所学校，用ForeignKey实现：

from django.db import models


class Director(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    first_name = models.CharField(max_length=50, verbose_name='Name')
    last_name = models.CharField(max_length=50, verbose_name='Surname')
    photo = models.ImageField(upload_to="uploads/img/", max_length=10000, verbose_name='photo')
    birthday = models.DateField(verbose_name='birthday')

    @property
    def full_name(self):
        return f"{self.first_name} {self.last_name}"

    def __str__(self):
        return self.full_name


class School(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    name = models.CharField(max_length=50, verbose_name='name')
    capacity = models.IntegerField(verbose_name='capacity')
    registration_is = models.BooleanField(verbose_name='Registration')
    # 用ForeignKey关联Director，指定反向关联名称
    director = models.ForeignKey(Director, on_delete=models.CASCADE, related_name='managed_schools', verbose_name='校长')

    def __str__(self):
        return self.name

使用示例 #

• 获取学校对应的校长全名：school.director.full_name
• 获取校长管理的所有学校名称：[school.name for school in director.managed_schools.all()]

内容的提问来源于stack exchange，提问作者Roberto-0F