Re: [Django] #34943: Support passing database expressions to bulk_create()'s unique_fields. (was: Support computed unique fields for INSERT ON CONFLICT ... UPDATE)

[Django]

#34943: Support passing database expressions to bulk_create()'s unique_fields.
-------------------------------------+-------------------------------------
Reporter: Alex Vandiver | Owner: nobody
Type: New feature | Status: new
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Mariusz Felisiak):

* cc: Vitor Pereira, Chih Sean Hsu (added)
* type: Uncategorized => New feature
* stage: Unreviewed => Accepted

Old description:

> #34277 added support for `INSERT ... ON CONFLICT(col1, col2) DO UPDATE
> SET ...` In some cases, however, the unique constraint may be on
> computed columns, which cannot be used with `unique_fields` because they
> are directly quoted.
>
> For instance:
> {{{#!python
> from django.db.models.functions import Upper
> UserTopic.objects.bulk_create(
> [ut],
> update_conflicts=True,
> update_fields=['last_updated','visibility_policy'],
> unique_fields=['user_profile_id','stream_id',Upper('topic_name')],
> )
> }}}
> ...fails because `UserTopic has no field named 'Upper(F(topic_name))'`.
>
> And:
> {{{#!python
> UserTopic.objects.bulk_create(
> [ut],
> update_conflicts=True,
> update_fields=['last_updated','visibility_policy'],
> unique_fields=['user_profile_id','stream_id','upper(topic_name)'],
> )
> }}}
> ...fails similarly, with `UserTopic has no field named
> 'upper(topic_name)'`.
>
> It would be a useful feature to be able to handle these cases.

New description:

#31685 added support for `INSERT ... ON CONFLICT(col1, col2) DO UPDATE SET
...` In some cases, however, the unique constraint may be on computed
columns, which cannot be used with `unique_fields` because they are
directly quoted.

For instance:
{{{#!python
from django.db.models.functions import Upper
UserTopic.objects.bulk_create(
[ut],
update_conflicts=True,
update_fields=['last_updated','visibility_policy'],
unique_fields=['user_profile_id','stream_id',Upper('topic_name')],
)
}}}
...fails because `UserTopic has no field named 'Upper(F(topic_name))'`.

And:
{{{#!python
UserTopic.objects.bulk_create(
[ut],
update_conflicts=True,
update_fields=['last_updated','visibility_policy'],
unique_fields=['user_profile_id','stream_id','upper(topic_name)'],
)
}}}
...fails similarly, with `UserTopic has no field named
'upper(topic_name)'`.

It would be a useful feature to be able to handle these cases.

--

Comment:

Sounds reasonable.

--
Ticket URL: <https://code.djangoproject.com/ticket/34943#comment:1>
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