'xxx' must be unique because it is referenced by a foreign key.

'xxx' must be unique because it is referenced by a foreign key.

原因：在绑定外键时，对应的外键字段的没有设置成唯一。

说明：在定义字段时，需要在被关联字段参数内添加unique=True

错误示例：

# UserInfo
Class UserInfo(models.Model):
    name = models.CharField(verbose_name="姓名",max_length=32)
# TaskInfo
class TaskInfo(models.Model):
   worker = models.ForeignKey(verbose_name="负责人",to="UserInfo",to_field="name",on_delete=models.CASCADE)

正确示例：

# UserInfo
Class UserInfo(models.Model):
    name = models.CharField(verbose_name="姓名",max_length=32,unique=True)