Re: Update _id field before .save() for ForeignKey

Hi guy,

I see this doc fix for u, with builtin pk in models django.

And you can create index in text/char field to optimize performance.

https://docs.djangoproject.com/en/dev/ref/databases/#manually-specified-autoincrement-pk

On Fri, Nov 29, 2019, 19:41 Maxim Bulatov <dvenum.at@gmail.com> wrote:

Hello,

I have lot of lists like follow:
(Name1): (V1, V2, V3, V4, ..)

And I use many threads to create many db objects:
company = Company(Name)
for x in vector:
    v = CompanyValue(company=company, value=x)
    values.append(v)

class CompanyValue(models.Model):
    company = models.ForeignKey('Company', on_delete=models.CASCADE)
    value = FloatField

This pool of threads return all lists, what I combine, filter and want put to database in one bulk_create call.
Suddenly, I found, company.id is not ready to be linked in CompanyValue, follow code does not works:
Company.objects.bulk_create(companies)
CompanyValue.objects.bulk_create(values)      # value.company_id is null here

No way to save objects in my threads, because I need to filter objects and can do it only when all of them are collected. Also, it has performance issues 100k+ of requests is slowly enough. I have two ways to resolve:
1. I can make intermediate class or tuple and create CompanyValue objects only when companies is saved to db. Hard to support, hard to filter, not so clean.
2. I can use dirty hack to update _id field:
    for v in values:
        v.company = v.company

Can you advice more ways for me? It seems, I don't know something from django features to make it elegant.
I see 11 years old issue here (https://code.djangoproject.com/ticket/9553) and it marked as intended behaviour.

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