#34378: Using in_bulk() with id_list and order_by()
-------------------------------------+-------------------------------------
Reporter: Ekaterina | Owner: nobody
Vakhrusheva |
Type: Bug | Status: new
Component: Database layer | Version: 4.1
(models, ORM) |
Severity: Normal | Resolution:
Keywords: ib_bulk | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by Ekaterina Vakhrusheva):
* stage: Accepted => Unreviewed
Old description:
> If you call in_bulk() together with the order_by(“field_1”,
> “field_2”).distinct(“field_1”) and specifying field_name=“field_1”, then
> when the result is received, the sorting order of the elements passed to
> order_by() is preserved. Code example:
>
> {{{
> locations = (
> UserLocation.objects.order_by("user_id", "-date_create")
> .distinct("user_id")
> .in_bulk(field_name="user_id")
> )
> print(locations)
> }}}
>
> **>>>{2693: <UserLocation: 2023-03-01 15:17>}**
>
> However, if you specify an additional id_list argument in the in_bulk
> method, the sorting specified earlier in the request disappears, and as a
> result, another instance of the model is returned. Code example:
>
> {{{
> locations = (
> UserLocation.objects.order_by("user_id", "-date_create")
> .distinct("user_id")
> .in_bulk([2693], field_name="user_id")
> )
> print(locations)
> }}}
>
> **>>>{2693: <UserLocation: 2023-03-01 14:27>}**
>
> A user with id 2693 has several locations that differ in the date_create.
> The most recent is with a time of **15:17**. When sorting queryset by
> “-date_create” I want to get the most recent record. Therefore, the
> sorting is reset when passing the id_list parameter.
>
> In my opinion, the sorting from queryset was removed before it was
> possible to pass different field_name to the in_bulk() method.
> Apparently, it was not taken into account that when sorting is reset, the
> result obtained when using DISTINCT changes.
>
> [https://forum.djangoproject.com/t/using-in-bulk/19192]
New description:
If you call in_bulk() together with the order_by(“field_1”,
“field_2”).distinct(“field_1”) and specifying field_name=“field_1”, then
when the result is received, the sorting order of the elements passed to
order_by() is preserved. Code example:
{{{
locations = (
UserLocation.objects.order_by("user_id", "-date_create")
.distinct("user_id")
.in_bulk(field_name="user_id")
)
print(locations)
}}}
**>>>{2693: <UserLocation: 2023-03-01 15:17>}**
However, if you specify an additional id_list argument in the in_bulk
method, the sorting specified earlier in the request disappears, and as a
result, another instance of the model is returned. Code example:
{{{
locations = (
UserLocation.objects.order_by("user_id", "-date_create")
.distinct("user_id")
.in_bulk([2693], field_name="user_id")
)
print(locations)
}}}
**>>>{2693: <UserLocation: 2023-03-01 14:27>}**
A user with id 2693 has several locations that differ in the date_create.
The most recent is with a time of **15:17**. When sorting queryset by
“-date_create” I want to get the most recent record. Therefore, the
sorting is reset when passing the id_list parameter.
In my opinion, the sorting from queryset was removed before it became
possible to pass different field_name to the in_bulk() method. Apparently,
it was not taken into account that when sorting is reset, the result
obtained when using DISTINCT changes.
[https://forum.djangoproject.com/t/using-in-bulk/19192]
--
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Ticket URL: <https://code.djangoproject.com/ticket/34378#comment:2>
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