#31340: Improve expression support for __search lookup and SearchQuery
-------------------------------------+-------------------------------------
Reporter: Baptiste Mispelon | Owner: Baptiste
| Mispelon
Type: New feature | Status: closed
Component: contrib.postgres | Version: dev
Severity: Normal | Resolution: fixed
Keywords: | Triage Stage: Ready for
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by David):
Does the current implementation works well with custom SQL functions which
returns {{{tsquery}}} and does not use any field which is already a
{{{tsquery}}}?
In one of my project I have created a custom SQL function which takes a
list of integers (the IDs of some row in a specific table) and builds a
{{{tsquery}}}. I tought that using the following it would work well while
it raises an exception
{{{#!python
class TheModel(models.Model):
searchable = SearchVectorField()
TheModel.objects.filter(searchable=models.Func(123, 345,
function='my_tsquery_func', output_field=SearchQueryField())
# django.db.utils.ProgrammingError: function plainto_tsquery(tsquery) does
not exist
}}}
Because the SQL produced is and this produces an exception.
{{{#!sql
SELECT id, searchable
FROM myapp_themodel
WHERE searchable @@ plainto_tsquery(my_tsquery_func(123, 345));
}}}
To add more context the {{{my_tsquery_func}}} looks like the following
(the goal is to combine {{{tsvector}}}s into a {{{tsquery}}} to build a
similarity algorithm):
{{{#!sql
CREATE OR REPLACE FUNCTION my_tsquery_func(first_id bigint, second_id
bigint) RETURNS tsquery AS $$
SELECT
to_tsquery(
array_to_string(
tsvector_to_array(
(SELECT searchable FROM myapp_themodel WHERE id =
first_id LIMIT 1)
|| (SELECT searchable FROM myapp_themodel WHERE id =
second_id LIMIT 1)
),
' | '
)
);
$$ LANGUAGE sql PARALLEL SAFE STABLE;
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/31340#comment:7>
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