#31839 closed New feature (wontfix)
Add additional database functions.
Reported by: | Nick Pope | Owned by: | Nick Pope |
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Component: | Database layer (models, ORM) | Version: | dev |
Severity: | Normal | Keywords: | functions, random, truncate, log2, log10, bit length, octet length, hyperbolic |
Cc: | Triage Stage: | Unreviewed | |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
I propose adding some additional database functions:
Random
-- generate random numbers in the range[0.0, 0.1)
.Truncate
-- round number towards zero. (SQL function isTRUNC
, butTrunc
is used for date truncation in Django.)Log2
andLog10
-- simple logarithm functions without needing to provide the base.ACosh
,ASinh
,ATanh
,Cosh
,Sinh
, andTanh
-- hyperbolic functions.BitLength
andByteLength
-- length of string in bits and bytes, complement toLength
which is character length.
Change History (6)
comment:1 by , 4 years ago
Has patch: | set |
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comment:2 by , 4 years ago
I'm not sure if it's worth adding extra database functions:
-
Log2
andLog10
can be achieved with proving base toLog
so I'm against them, - hyperbolic functions are supported only on PostgreSQL 12+, we need to emulate them on other DBs, it's not worth, IMO,
BitLength
andOctetLength
will probably not work on Oracle.
Truncate
and Random
sound reasonable.
comment:3 by , 4 years ago
Description: | modified (diff) |
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comment:4 by , 4 years ago
Resolution: | → wontfix |
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Status: | assigned → closed |
I think we need to decide at what point we say enough is enough here, and recommend users create their own functions like we did with template tags. For me hyperbolic functions cross that line. You can start a discussion on DevelopersMailingList if you don't agree. Personally I've never used any of proposed database functions.
comment:5 by , 4 years ago
Will you still take Random
and Truncate
?
In the case of Random
there is also a nice bit of simplification:
https://github.com/django/django/commit/c8913d41e74859747893dc21356a1fb6906c56e9
comment:6 by , 4 years ago
Random()
is already there (as an expression) so we can change it to a function and promote in docs, I'm just not sure why we change its behavior.
Truncate()
can be confused with Trunc()
for dates/datetimes, and we can achieve the same by using Cast(..., models.IntegerField())
so I don't think it's necessary.
PR