Question

I have a simple Django model resembling:

class Address(models.Model):
    blah

class MemberData(models.Model):
    user = models.ForeignKey(User)
    addresses = models.ManyToManyField(Address)

I want to expose the Address model in admin to allow a user to filter Address records by their associated user. e.g.

class AddressAdmin(admin.ModelAdmin):
    model = Address
    list_filter = [???]

The ModelAdmin.list_filter property allows this, but I’m not sure what field name to use to support my many-to-many relationship. If the Address model has a direct reference to the MemberData model, I could do something like:

class AddressAdmin(admin.ModelAdmin):
    model = Address
    list_filter = ['memberdata__user']

Is there any equivalent syntax for an indirect many-to-many relationship? If not, is there any workaround to accomplish the same end?

Answer 1

I believe in a case like this, you could make a trivial through model for your M2M relation, and then use the normal syntax to follow the (now explicit) ForeignKeys. Something like:

class Address(models.Model):
    blah

class MemberData(models.Model):
    user = models.ForeignKey(User)
    addresses = models.ManyToManyField(Address,through='MemberAddress')

class MemberAddress(models.Model):
    member = models.ForeignKey(MemberData)
    address = models.ForeignKey(Address)

and in the admin:

class AddressAdmin(admin.ModelAdmin):
    model = Address
    list_filter = ['memberaddress_set__member__user']