Django管理员未显示记录，但仍显示数字

Question

我有一个带有外键 且没有db_constraint的模型。我这样做是为了插入可能不指向外部表的值。我能够正确导入值。

在Django管理员中，如果我查看包含无约束外键的模型类型，则看不到模型，但确实看到了一定数量的模型。

这是我的代码

class HlaType(models.Model):
  specimen = models.ForeignKey(SpecimenInfo, on_delete=models.CASCADE, verbose_name="Specimen",
                             related_name="hlatype", db_constraint=False)
  allele_key = models.CharField(max_length=5, db_index=True)
  allele = models.CharField(max_length=50, blank=True, db_index=True)

  class Meta:
      constraints = [
          models.UniqueConstraint(fields=('specimen', 'allele_key'), name='targets_hlatype_unique_specimen_and_key')
      ]

class HlaTypeAdmin(ImportExportMixin, admin.ModelAdmin):
  raw_id_fields = ["specimen"]
  list_display = ('specimen', 'allele_key', 'allele')
  resource_class = HlaTypeResource
  list_per_page = 200

class HlaTypeResource(ModelResource):
  specimen = Field(attribute='specimen', column_name='specimen_id', widget=HlaWidget(SpecimenInfo, 'pk'))
  allele_key = Field(attribute='allele_key', column_name='allele_key')
  allele = Field(attribute='allele', column_name='allele')

  class Meta:
      model = HlaType
      import_id_fields = ('specimen', 'allele_key')
      skip_unchanged = True
      fields = ('id', 'specimen', 'allele_key', 'allele')

有什么办法可以解决这个问题吗？