#36673 closed New feature (duplicate)
DecimalField max_digits and decimal_places should be optional and more general
| Reported by: | Gavin Wahl | Owned by: | |
|---|---|---|---|
| Component: | Database layer (models, ORM) | Version: | 5.2 |
| Severity: | Normal | Keywords: | |
| Cc: | Gavin Wahl | Triage Stage: | Unreviewed |
| Has patch: | no | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
In Postgres and the SQL standard, it is not necessary to define a precision and scale for NUMERIC/DECIMAL fields. However, Django requires that they be specified.
https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-NUMERIC-DECIMAL
I would like to be able to create an unconstrained NUMERIC field with DecimalField(), but Django gives the error:
(fields.E130) DecimalFields must define a 'decimal_places' attribute. fields.E132) DecimalFields must define a 'max_digits' attribute.
Also, the precision needs to be allowed to be less than the scale. NUMERIC(1,2) is a valid type that stores numbers of the form -0.00, -0.01,...0.08, 0.09 but Django says:
(fields.E134) 'max_digits' must be greater or equal to 'decimal_places'.
Change History (6)
comment:1 by , 8 hours ago
| Cc: | added |
|---|---|
| Component: | Uncategorized → Database layer (models, ORM) |
comment:2 by , 6 hours ago
| Resolution: | → duplicate |
|---|---|
| Status: | new → closed |
| Type: | Uncategorized → New feature |
comment:3 by , 3 hours ago
That's a bug in inspectdb, related to floating-point fields (approximate) in Oracle--I don't understand how it's a duplicate of this. I just want to remove the overly-aggressive validation when using DecimalField (exact).
comment:4 by , 2 hours ago
Introspection fails because Django doesn't have any way to represent numeric with unlimited precision. That representation is what you've requested.
comment:5 by , 2 hours ago
That ticket requests an "ImpreciseDecimalField" to represent floating-point (approximate) fields. Django's DecimalField is used to represent exact values.
The Oracle inspectdb bug from the mailing list and ticket look like a floating-point Oracle field getting incorrectly introspected as a DecimalField instead of FloatField (perhaps this was before FloatField existed?). I can contribute a patch to fix the DecimalField validation; I can't fix Oracle introspection.
comment:6 by , 2 hours ago
We should comment on #24920 to denote that it's not only about introspection but I agree with Tim's triage here it's better to focus work in a single ticket and gain introspection support along the way particularly because the other ticket is so old and more importantly an accepted feature which doesn't require going through the updated new feature proposal.
Duplicate of #24920.