#32858: Syntax error when using an index transform on an ArrayField in an
ExclusionConstraint
-------------------------------------+-------------------------------------
Reporter: Lucidiot | Owner: nobody
Type: Bug | Status: new
Component: Database | Version: 3.2
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
I am trying to create a GIST exclusion constraint on a PostgreSQL 12
database. One of the fields is an ArrayField, and I want to apply the
constraint on its first item using `my_array__0`. When doing so, I get a
syntax error from Postgres.
{{{#!python
from django.db import models
from django.contrib.postgres.constraints import ExclusionConstraint
from django.contrib.postgres.fields import ArrayField, RangeOperators
class MyModel(models.Model):
my_array = models.ArrayField()
class Meta:
constraints = (
ExclusionConstraint(
name='foo',
expressions=[
('my_array__0', RangeOperators.EQUAL),
]
)
)
}}}
{{{
django.db.utils.ProgrammingError: syntax error at or near "WITH"
LINE 1: ..." ADD CONSTRAINT "foo" EXCLUDE USING GIST ("my_array"[1] WITH
=)
^
}}}
It seems a similar issue had occurred with casts (#32392). The
[https://www.postgresql.org/docs/current/sql-altertable.html docs for
ALTER TABLE] mention this syntax for expressions in an EXCLUDE constraint:
{{{
exclude_element in an EXCLUDE constraint is:
{ column_name | ( expression ) } [ opclass ] [ ASC | DESC ] [ NULLS {
FIRST | LAST } ]
}}}
This implies that parentheses around anything that is not a column name
are mandatory. Maybe a more generic fix could be made to detect if
something is only a column name, or just to add parentheses all the time?
`EXCLUDE USING GIST (("my_array"[1]) WITH =)` works without any trouble.
--
Ticket URL: <https://code.djangoproject.com/ticket/32858>
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 view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/051.e1967961fefb83447260ffc38c8b7b5d%40djangoproject.com.
