Django GenericTabularInline for multiple databases - django

Question

I've been trying to make the GenericTabularInline class work in a two-admin two-databases setup by inheriting from it and overriding some methods in the BaseModelAdmin class, as is done in the Django docs (https://docs.djangoproject.com/en/dev/topics/db/multi-db/), but if a child model is edited in the inline form, it always writes to the default database (I want the second admin to deal exclusively with a secondary database, models are the same for both), so I must not be overriding some method(s) or doing something wrong. Here's the class I have so far:
class MultiDBGenericTabularInline(generic.GenericTabularInline):
using = settings.SECONDARY_DATABASE
def save_model(self, request, obj, form, change):
# Tell Django to save objects to the 'other' database.
obj.save(using=self.using)
def delete_model(self, request, obj):
# Tell Django to delete objects from the 'other' database
obj.delete(using=self.using)
def queryset(self, request):
# Tell Django to look for objects on the 'other' database.
return super(MultiDBGenericTabularInline, self).queryset(request).using(self.using)
def formfield_for_foreignkey(self, db_field, request=None, **kwargs):
# Tell Django to populate ForeignKey widgets using a query
# on the 'other' database.
return super(MultiDBGenericTabularInline, self).formfield_for_foreignkey(db_field, request=request, using=self.using, **kwargs)
def formfield_for_manytomany(self, db_field, request=None, **kwargs):
# Tell Django to populate ManyToMany widgets using a query
# on the 'other' database.
return super(MultiDBGenericTabularInline, self).formfield_for_manytomany(db_field, request=request, using=self.using, **kwargs)
#Override these three methods; otherwise the log manager attempts
#to write to the main db and raises an exception.
def log_addition(self, request, object):
pass
def log_change(self, request, object, message):
pass
def log_deletion(self, request, object, object_repr):
pass
Any help or hints are appreciated.

Answer 1

I realize this is an old question, but I've stumbled across a very similar thing recently. The trick is to override the parent Model Admin's save_formset method. In my case, the solution is to do something like this:
class SomeTabularInline(admin.TabularInline):
# stuff
class MyModelAdmin(admin.ModelAdmin):
using = 'something'
inlines = (SomeTabularInline,)
def save_formset(self, request, form, formset, change):
instances = formset.save(commit=False)
for obj in formset.deleted_objects:
obj.delete(using=self.using)
for instance in instances:
instance.save(using=self.using)
formset.save_m2m()
Note: I'm using a TabularInline instance, and not a GenericTabularInline but they both descend from InlineModelAdmin; so I'm hopeful that this would work in your case.
Source: https://docs.djangoproject.com/en/1.9/ref/contrib/admin/#django.contrib.admin.ModelAdmin.save_formset