#34078: Should the Postgres range_merge aggregate be added to postgres.contrib?
-------------------------------------+-------------------------------------
Reporter: Jack | Owner: (none)
Linke |
Type: New | Status: new
feature |
Component: | Version: 4.1
contrib.postgres | Keywords: postgres range
Severity: Normal | range_merge aggregation aggregate
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
Most of the Postgres range functions have been exposed for querying in
django, but not the {{{range_merge}}} Aggregate function.
As background, {{{range_merge}}} "Computes the smallest range that
includes ... the given ranges".
The existing Postgres functions exposed for queries in django:
https://docs.djangoproject.com/en/4.1/ref/contrib/postgres/fields
/#querying-using-the-bounds
The full list of Posgres range functions (note that range_merge is the
only one not represented in django): https://www.postgresql.org/docs/14
/functions-range.html#RANGE-FUNCTIONS-TABLE
----
To make use of this aggregation in my own project, I created a django
package that runs a migration to CREATE (or DROP) the aggregate function
in the database (https://pypi.org/project/django-range-merge/).
{{{
operations = [
migrations.RunSQL(
sql=[("CREATE OR REPLACE AGGREGATE
range_merge(anyrange)(sfunc=range_merge, stype=anyrange);")],
reverse_sql=[("DROP AGGREGATE IF EXISTS range_merge(anyrange);")],
)
]
}}}
Then, given the model:
{{{
class Event(models.Model):
name = models.CharField(max_length=30)
potential_visitors = models.IntegerRangeField()
}}}
And a few model instances:
{{{
{"id" : 1, "name" : "Birthday", "potential_visitors" : "[2, 3)"}
{"id" : 2, "name" : "Bake Sale", "potential_visitors" : "[30, 50)"}
{"id" : 3, "name" : "Band Camp", "potential_visitors" : "[22, 28)"}
{"id" : 4, "name" : "Cooking Show", "potential_visitors" : "[7, 20)"}
{"id" : 5, "name" : "Pajama Day", "potential_visitors" : "[15, 30)"}
}}}
Executing the query:
{{{
Event.objects.all().aggregate(
output=Aggregate(F("potential_visitors"), function="range_merge")
)
}}}
Returns:
{{{{'output': NumericRange(2, 50, '[)')}}}}
----
It looks like RunSQL is not used anywhere in django's codebase, except in
tests, so I am not sure if adding this to the contrib.postgres codebase
would be welcomed.
Should this be added to django, or should it remain as a package separate
from django itself?
--
Ticket URL: <https://code.djangoproject.com/ticket/34078>
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 django-updates+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/01070183bb857284-c88db069-3152-4296-a589-0543d7c694c3-000000%40eu-central-1.amazonses.com.
