进入到django自带的related.py中,可以看到
1.ForeignKey
初始化的参数有:
to, on_delete, related_name=None,
related_query_name=None,limit_choices_to=None,
parent_link=False, to_field=None,
db_constraint=True, **kwargs
假设我们有:
class Author(models.Model):
author = models.CharField(max_length=250)
class Books(models.Model):
book = models.ForeignKey(to='Author',on_delete=models.CASCADE,to_field='id')
to:被关联表的名称
on_delete:删除带有外键的信息时,定义了删除的操作:
to_field:被关联的字段,一般是主键,也可以是值唯一的字段
2.OneToOne
初始化参数有:
to, on_delete, to_field=None, **kwargs
3.ManyToMany
初始化参数有:
to, related_name=None, related_query_name=None,
limit_choices_to=None, symmetrical=None, through=None,
through_fields=None, db_constraint=True, db_table=None,
swappable=True, **kwargs
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