I tried the to_field argument, that was a mistake, and I put it back.
I was just inserting the pk of the foreign object. However, as things are
moving through the pipeline, I used uuid.uuid4() to create additional pks
as needed at it went along.
Example:
def process_item(self, item, spiders):
itemcasebycase['case_arrow'] = item['uniqid']
itemcasebycase['uniqid'] = get_u
But this is what works in the pipeline:
scotus = Jurisdiction.objects.get(
uniqid='5e4dd0c2-5cc9-4d08-ab43-fcf0e84dfc44')
item['jurisdiction'] = scotus
And this is the error message I got:
ValueError: Cannot assign "UUID('5e4dd0c2-5cc9-4d08-ab43-fcf0e84dfc44')":
"Case.jurisdiction" must be a "Jurisdiction" instance
Finally, yes, under normal circumstances, my pk uuids are made
automatically. Thanks
*“None of you has faith until he loves for his brother or his neighbor what
he loves for himself.”*
On Mon, Mar 5, 2018 at 2:16 PM, Bill Freeman <[email protected]> wrote:
> Are you specifying the to_field argument, or are you letting it default?
>
> And is the pk of the other model made by Django by default, or are you
> explicitly specifying a foreign key constraint on some field of your own.
>
> Things might be better in 2.0, but I've had my troubles with pk that isn't
> an AutoField (such as made by default).
>
> If you're only doing the standard (defaulted) stuff, it's a mystery.
> Either way folks probably need to see some of your code to help out.
>
> On Mon, Mar 5, 2018 at 5:06 PM, Malik Rumi <[email protected]> wrote:
>
>> Hello all,
>>
>> Up to now, (admittedly not long - I'm not a total newbie but I still have
>> a LOT to learn) when making a foreign key I would just put the pk of that
>> instance in the fk field, as the docs suggest:
>>
>> By default ForeignKey will target the pk of the remote model but this
>> behavior
>> can be changed by using the ``to_field`` argument.
>>
>> *https://docs.djangoproject.com/en/2.0/_modules/django/db/models/fields/related/#ForeignKey
>> <https://docs.djangoproject.com/en/2.0/_modules/django/db/models/fields/related/#ForeignKey>
>> *
>>
>> However, recently while working with a scrapy pipeline, these fields
>> started catching errors, which told me
>>
>> "...must be an instance of ...(foreign object)"
>>
>> And sure enough, if I did a get queryset for the one specific instance in
>> question, that worked. My question is why, or maybe it should be, what's
>> the difference, or maybe even, what's going on here, or wtf?
>>
>> Any light you can shed on this for me would, as always, be greatly
>> appreciated.
>>
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