Django CreateView多对象插入

Question

I no have an idea what title should be, but here I have a case that if a form was submitted it will find data from other model and insert every matched.

currently here my code.

here my models.py

class Foo(models.Model):
    name = models.CharField()
    value = models.DecimalField()

class Bar(models.Model):
    name = models.CharField()
    date = models.DateField()
    foo = models.ForeignKey(Foo, related_name='foo')

here my views.py

class Foo(CreateView):
    fields = ('name', 'value')
    model = models.Foo

    def form_valid(self, form):
        self.object = form.save(commit=False)
        for i in range(30):
            self.object.bar.foo.append(self.object.id)


        return super(ModelFormMixin, self).form_valid(form)

Bar have ForeignKey to Foo example if form was submitted with range(30) it will find Bar and insert ( append ) Foo id for every data. now i do with this,

self.object.bar.foo.append(self.object.id) but error said 'Foo' object has no attribute 'bar'

how to insert append multiple data to Bar from Foo(CreateView) ?...

Answer 1

First of all, append is method of list , and FK relation is definitely not a list. Secondly, you have used related_name='foo' in your Bar model, so actually you can get Bar from Foo by using foo.foo . I am sure this is an error. As long as one Foo can have many Bar , your related_name should be bars , so you would be able to use foo.bars.all() . To create Bar , you should firstly save your Foo , so use commit=True .
And the last. In your for loop use Bar.objects.create(foo=self.object) . Your also would like to use bulk_create to optimize that loop, so you don't make 30 queries to databases but just one. To implement it, create a list bars = [] before loop. Than inside loop use bars.append(Bar(foo=self.object) . Here append is method of list , so your are just creating a list of Bar objects without saving them to database. And finally after loop use Bar.objects.bulk_create(bars) to actually save them to database.

I have reread your question and maybe I have missed the point. How do you want to 'find' your Bar ? Also, you can't add multiple Foo to your Bar , because it if FK which means single object.