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?
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