#25774: Refactor of datetime expressions and better, official support for right-
hand-side date part extraction
-------------------------------------+-------------------------------------
Reporter: ryuusenshi | Owner: nobody
Type: New feature | Status: new
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
db,expressions,date,time,extract,transform| Unreviewed
Has patch: 1 | Needs documentation: 1
Needs tests: 1 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by ryuusenshi):
* needs_docs: => 1
* needs_tests: => 1
* needs_better_patch: => 0
Old description:
> As previously stated in [https://code.djangoproject.com/ticket/25556 this
> ticket] and [https://groups.google.com/forum/#!topic/django-
> developers/GU8OrPUMjrc this thread], I have begun work on the following:
>
> - making the so called datetime transforms (currently residing in
> `django.db.models.lookups`) part of the officially supported ORM API as
> part of the db expressions,
> - making these transforms easily usable on the right hand side of
> lookups / Q objects
> [[BR]]
>
> To this effect, I propose the following:
> - replace module `django.db.models.expressions` with a package of
> the same name
> - add module `django.db.models.expressions.datetimes`
> - rename `XTransform` to `XExtract` and move them from
> `django.db.models.lookups` to `django.db.models.lookups` to
> `django.db.models.expressions.datetimes`
> - change `YearLookup` and `YearComparisonLookup` to allow for
> functions on the right hand side
> - extensive testing of these db expressions
> - adding this to the release notes
> - any other change that might support this
>
> [[BR]]
>
> I'm also adding a [PR] with some of these already implemented. What
> remains to be done is:
> - replace references `XTransform` type classes in
> `django.db.models.lookups` with `XExtract` classes from
> `django.db.models.expressions.datetimes`
> - replace these references anywhere else in the project (I've noticed
> there are some in the tests, for instance)
>
> [[BR]]
>
> With the API in the [PR] it becomes possible to do the following lookup:
>
> {{{
> from django.db.models.expressions.datetimes import DateExtract
>
> Person.objects.filter(birth_date__year=DateExtract('job__start_date',
> lookup_name='year'))
> }}}
>
> which is equivalent to:
>
> {{{
> from django.db.models.expressions.datetimes import YearExtract
>
> Person.objects.filter(birth_date__year=YearExtract('job__start_date'))
> }}}
>
> Additionally, @jarshwah suggested that these should maybe be named:
> `ExtractX` instead of `XExtract`.
New description:
As previously stated in [https://code.djangoproject.com/ticket/25556 this
ticket] and [https://groups.google.com/forum/#!topic/django-
developers/GU8OrPUMjrc this thread], I have begun work on the following:
- making the so called datetime transforms (currently residing in
`django.db.models.lookups`) part of the officially supported ORM API as
part of the db expressions,
- making these transforms easily usable on the right hand side of
lookups / Q objects
[[BR]]
To this effect, I propose the following:
- replace module `django.db.models.expressions` with a package of the
same name
- add module `django.db.models.expressions.datetimes`
- rename `XTransform` to `XExtract` and move them from
`django.db.models.lookups` to `django.db.models.lookups` to
`django.db.models.expressions.datetimes`
- change `YearLookup` and `YearComparisonLookup` to allow for
functions on the right hand side
- extensive testing of these db expressions
- adding this to the release notes
- any other change that might support this
[[BR]]
I'm also adding a [https://github.com/django/django/pull/5683 PR] with
some of these already implemented. What remains to be done is:
- replace references `XTransform` type classes in
`django.db.models.lookups` with `XExtract` classes from
`django.db.models.expressions.datetimes`
- replace these references anywhere else in the project (I've noticed
there are some in the tests, for instance)
[[BR]]
With the API in the [https://github.com/django/django/pull/5683 PR] it
becomes possible to do the following lookup:
{{{
from django.db.models.expressions.datetimes import DateExtract
Person.objects.filter(birth_date__year=DateExtract('job__start_date',
lookup_name='year'))
}}}
which is equivalent to:
{{{
from django.db.models.expressions.datetimes import YearExtract
Person.objects.filter(birth_date__year=YearExtract('job__start_date'))
}}}
Additionally, @jarshwah suggested that these should maybe be named:
`ExtractX` instead of `XExtract`.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25774#comment:1>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/068.ac6d8457ec653172bfc8ac236aace99b%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
