Django：从关系中检索对象

Question

我是 Django 的新手（使用过 1.11），我读过这篇文章（https://docs.djangoproject.com/fr/1.11/topics/db/models/），但我没有为我的问题找到明确的答案：如何检索对象

举个例子，假设我有以下模型：

class StudentCollaborator(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    code_postal = models.IntegerField()
    collaborative_tool = models.BooleanField(default=False)

    def get_skills(self):
        return SkillHistory.objects.filter(student=self.user, value="acquired").values_list('skill')

技能历史：

class SkillHistory(models.Model):
    """
        The reason why a Skill is acquired or not,
        or not yet, when and by who/how

    """

    skill = models.ForeignKey(Skill)
    """The Skill to validate"""
    student = models.ForeignKey('users.Student')
    """The Student concerned by this Skill"""
    datetime = models.DateTimeField(auto_now_add=True)
    """The date the Skill status was created"""
    value = models.CharField(max_length=255, choices=(
        ('unknown', 'Inconnu'),
        ('acquired', 'Acquise'),
        ('not acquired', 'None Acquise'),
    ))
    """The Skill status : unknown, acquired or not acquired"""

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    reason_object = GenericForeignKey('content_type', 'object_id')
    reason = models.CharField(max_length=255)
    """Why the Skill is validated or not"""

    by_who = models.ForeignKey(User)

    class Meta:
        ordering = ['datetime']

最后是技能课：

class Skill(models.Model):
    """[FR] Compétence

        A Skill can be evaluated through questions answered by a student.
        Thus, when evaluated, a Skill can be acquired by a student, or not.

    """

    code = models.CharField(max_length=20, unique=True, db_index=True)
    """The Skill reference code"""

    name = models.CharField(max_length=255)
    """The Skill name"""

    description = models.CharField(max_length=255)

如何在 get_skills 函数中检索技能对象（而不是其 ID）；谢谢？

谢谢

Answer 1

您无法直接获取 Skill 对象。但是你可以通过这个查询获得技能属性。

SkillHistory.objects.filter(student=self.user, value="acquired").values('skill__name', 'skill__code')

Answer 2

Skill.objects.filter(skillhistory_set__student=self.user, skillhistory_set__value="acquired")

使用相关名称过滤。