id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
36030	SQLite backend unnecessarily applies AS NUMERIC cast when preparing python Decimals	Bartłomiej Nowak		"After two rounds of triage and a third round of investigation, the most current thinking about the requirements for this ticket can be found at
comment:18 and comment:25.


Original report follows, but be aware that comment:18 and comment:25 describe this as more or less expected behavior:
----

When I am using Decimal at Python level, I expect to use numeric type on database level. But it seems to depend on string formatting of decimal itself instead of type of object. 

**See examples:**

`Decimal(1000.0)` --> will render as `1000` at query and will be **INT** on db level.
`Decimal(1000)`  --> will render as `1000` at query and will be **INT** on db level.
`Decimal(""1000.0"")` -> will render as `1000,0` at query and will be **NUMERIC** on db level.
`models.Value(1000.0, output_field=DecimalField())` ->  will render as `1000` at query and will be **INT** on db level.
`models.Value(1000.0)` (no decimal provided as above) -> will render as `1000,0` at query and will be **NUMERIC** on db level.

It leads to bugs, cuz at DB LVL,  INT / INT is also INT (2/3 = 0), and I doubt anyone who provides decimal there, excepts that behavior.

=============
I am using Postgres. 

{{{
SomeModel.objects.create(some_field_of_type_int=2)
sm = SomeModel.objects.annotate(x=F(""some_field_of_type_int"") / Decimal(3.0)).get()
sm.x # returns Decimal of 0
}}}

It will render Decimal of 3.0 to the query as 3 (INT). Because str(...) from Decimal(3.0) returns 3. (See cases at description)
At python is not a problem, but at database it is, cus it breaks types. Calculation of two INTs at postgres, will return int as well, which is in this case 0, instead of 0.6666, which database would produce, if Django would render 3.0 instead of 3.

Therefore, Django will return Decimal('0'), which I consider as Bug. This is not what anyone suppose to get. 
============="	Bug	new	Database layer (models, ORM)	dev	Normal		division decimalfield	Bartłomiej Nowak	Accepted	0	0	0	0	0	0