Django ManyToManyField 指定了一个中介模型。通过 OneToOneField 关系

Question

我有一个我在研究中没有遇到过的模型设置。这是一个具有直通关系 table 的模型，即 OneToOne 关系。

问题是在表单中设置预订时管理界面工作正常。

 class AgentForm(forms.ModelForm):
     class Meta:
         model = Agent

但是创建 Basic ModelForm 会导致错误：

AttributeError: Cannot set values on a ManyToManyField which specifies an intermediary model.  Use podman.BladeReservation's Manager instead.

models.py

class Node(models.Model):
    name = models.CharField(_('Name'), help_text=_('A name for the node.'), max_length=128)
    hostname = models.CharField(
        verbose_name=_('Hostname'),
        max_length=255,
        blank=True, null=True
    )
    class Meta:
        abstract = True
        ordering = ['name', 'hostname']

class Blade(Node):
    serial_number = models.CharField(_('Serial Number'), max_length=255, unique=True)
    uuid = models.CharField(
        verbose_name=_('UUID'),
        help_text=_('Node UUID'),
        max_length=50,
        null=True, blank=True
    )
    ...

class Agent(models.Model):
    name = models.CharField(_('Name'), max_length=128, help_text=_('This name is a friendly handle for humans.'))
    slug = models.SlugField(
        verbose_name=_(u'Slug'),
        help_text=_('Uri identifier. This name is the lookup key for Automation'),
        max_length=100,
        unique=True
    )
    ...

    blades = models.ManyToManyField('podman.Blade', related_name='blades', through='podman.BladeReservation')
    ...

class BladeReservation(models.Model):
    blade = models.OneToOneField('podman.Blade')
    agent = models.ForeignKey('podman.Agent')
    reserved_until = models.DateTimeField(null=True, blank=True)

admin.py

class AgentAdmin(CompareNoDuplicates):
    prepopulated_fields = {'slug': ('name',)}
    inlines = [BladeReservationInline]
    filter_horizontal = ('blades',)
    list_display_links = ('__str__',)
    preserve_filters = True

class BladeReservationInline(admin.TabularInline):
    model = BladeReservation

    def get_formset(self, request, obj=None, **kwargs):
        kwargs['formfield_callback'] = partial(self.formfield_for_dbfield, request=request, obj=obj)
        return super(BladeReservationInline, self).get_formset(request, obj, **kwargs)

    def formfield_for_dbfield(self, db_field, **kwargs):
        agent = kwargs.pop('obj', None)
        formfield = super(BladeReservationInline, self).formfield_for_dbfield(db_field, **kwargs)
        if db_field.name == "blade" and agent:
            formfield.queryset = formfield.queryset.filter(chassis__pod__in=[p for p in agent.container.pods.all()])
        return formfield

我目前的轨道是制作一个 WizardView 只是为了获得自定义表单流，但它并不理想。任何想法将不胜感激。

Answer 1

您很可能会收到此错误，因为您尝试直接创建 Agent-Blade 关系，但是 docs 说：

You can’t just create a relationship between a Person and a Group - you need to specify all the detail for the relationship required by the Membership model. The simple add, create and assignment calls don’t provide a way to specify this extra detail. As a result, they are disabled for many-to-many relationships that use an intermediate model. The only way to create this type of relationship is to create instances of the intermediate model.

但是由于 BladeReservation 模型中的 reserved_until 字段允许为空，这可能对您有所帮助：

class BladeReservation(models.Model):
    # ...
    class Meta():
        auto_created=True

Django ManyToManyField 指定了一个中介模型。通过 OneToOneField 关系

Django ManyToManyField which specifies an intermediary model. Through a OneToOneField Relationship

python

forms

django

django-forms