Hi!
I would like to provide an example of why this field is needed.
In PostgreSQL, a floating point literal like 4.6 has type decimal, not
binary floating point (see SELECT pg_typeof(4.6)).
When comparing binary floating point values to decimals, the decimal is
converted to double precision binary floating point value. This make
FloatField work.
But if you have real/float4 fields and you compare them to decimal value,
it doesn't work.
Here is an example, with a workaround.
in bar/models.py
from django.db import models
from django.db.models import FloatField
class RealField(FloatField):
def db_type(self, connection):
return 'real'
class Thing(models.Model):
score = RealField(null=False)
and now in shell:
from django.db.models import Value
from django.db.models.functions import Cast
from bar.models import RealField, Thing
Thing(score=4.6).save()
Thing.objects.all()[0].score
4.6
Thing.objects.filter(score=4.6).first()
None
str(Thing.objects.filter(score=4.6).query)
SELECT "bar_thing"."id", "bar_thing"."score" FROM "bar_thing" WHERE
"bar_thing"."score" = 4.6
Thing.objects.filter(score=Cast(Value(4.6), RealField())).first()
<Thing: Thing object (1)>
str(Thing.objects.filter(score=Cast(Value(4.6), RealField())).query)
SELECT "bar_thing"."id", "bar_thing"."score" FROM "bar_thing" WHERE
"bar_thing"."score" = (4.6)::real
Can Django have a RealField that automatically does the cast?
--
<https://swampup.jfrog.com/?utm_source=email&utm_medium=footer&utm_campaign=emea_sales&utm_term=city-tour-22>
--
You received this message because you are subscribed to the Google Groups
"Django developers (Contributions to Django itself)" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-developers+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-developers/068b4121-d28c-4bd7-997e-7fc5d499119en%40googlegroups.com.
