"Django保存新对象时出现唯一约束失败错误"

Question

我有这个型号：

#models.py
class Enrollment(models.Model):
    student = models.ForeignKey(User, on_delete=models.PROTECT)
    curriculum = models.ForeignKey(Curriculum, on_delete=models.PROTECT)
    enrolment_date = models.DateTimeField(null=True,blank=True,auto_now_add=True)
    payed_amount = models.PositiveIntegerField(null=True,blank=True)
    is_complete_paid = models.BooleanField(null=True,blank=True,default=False)

    class Meta:
        unique_together = (("student", "curriculum"),)

当我想用以下代码在我的views.py中创建新注册时：

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我有个错误：

UNIQUE constraint failed: lms_enrollment.student_id, lms_enrollment.curriculum_id

为什么会发生这个错误？是否可以解释此错误的原因并介绍一些相关文档？在

Answer 1

class Enrollment(models.Model):
    student = models.ForeignKey(User, on_delete=models.PROTECT)
    curriculum = models.ForeignKey(Curriculum, on_delete=models.PROTECT)
    payed_amount = models.PositiveIntegerField(null=True, blank=True)

    class Meta:
        unique_together = (("student", "curriculum"),)

在Meta.unique一起这意味着数据库中的两个字段不能超过1

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