列“id”中的IntegrityError-null值违反非空约束DETAIL：失败行包含（null，0,176,243）

Question

我使用了postgresql，我的django模型是

 class SelectResources(models.Model):
        collection_resource = models.ForeignKey(
            'wagtailcore.Page',
            null=True,
            blank=True,
            on_delete=models.SET_NULL,
            related_name='+'
        )

    content_panels = Page.content_panels + [
        PageChooserPanel('collection_resource'),
    ]

    class Meta:
        abstract = True

class ResourcePageSelectResources(Orderable, SelectResources):
    page = ParentalKey('ResourceCollections', related_name='selectresources')

class ResourceCollections(ResourcePage):
    collection_cover_image = models.ForeignKey(
        'wagtailimages.Image',
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name='+',
        help_text="""
            Max file size: 10MB. Choose from: JPEG, PNG
        """
    )
    image_text = RichTextField(blank=True,
        help_text="Text that displays hover the image"
    )
    body_text = TextField(blank=True,
        help_text="Text that displays on the body"
    )
    collection_heading = TextField(blank=True,
        help_text="Heading of collections"
    )
    description = TextField(blank=True,
        help_text="Short description of collections"
    )
    button_text = TextField(blank=True)

    content_panels = Page.content_panels + [
        ImageChooserPanel('collection_cover_image'),
        FieldPanel('image_text', classname="full"),
        FieldPanel('body_text', classname="full"),
        FieldPanel('collection_heading', classname="full"),
        FieldPanel('description', classname="full"),
        FieldPanel('button_text', classname="full"),
        InlinePanel('selectresources', label="selectresources"),
    ]

    promote_panels = Page.promote_panels + [
        FieldPanel('topic_tags'),
        FieldPanel('priority'),
    ]

    def get_context(self, request, **kwargs):
        slug = ''
        context = super(ResourceCollections, self).get_context(request)
        context = get_data(
            request, data=context, slug=slug,
            path_components=kwargs.get('path_components', [])
        )
        return base_context(context,self)

    def get_template(self, request):
        return 'resources/collections_index_page.html'

当我尝试在wagtail admin中使用SelectedResources发布页面时，它会抛出错误列“id”中的IntegrityError-null值违反非空约束DETAIL：失败行包含（null，0,176,243 ）

没有SelectedResources，页面按预期正确发布