#28643: Complete the ORM Function Library
-------------------------------------+-------------------------------------
Reporter: Matthew Pava | Owner: JunyiJ
Type: New feature | Status: assigned
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Nick Pope:
Old description:
> I was surprised to learn that we didn't have a StrIndex function until
> version 2, and yet we had Substr since at least version 1.8. I wonder
> how users were using Substr without also finding a use for StrIndex this
> whole time. Anyway, since we seem to be adding these functions one at a
> time, why don't we work on trying to get the built-ins implemented in one
> sweep instead?
>
> We may even want to split the documentation page
> (https://docs.djangoproject.com/en/dev/ref/models/database-functions/)
> into further categories with String functions and Numeric functions.
>
> This is just a sample checklist, with corresponding attributes to which
> backend has them available.
>
> ||||||||||||||= **Comparison** =||
> ||**Name**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
> ||{{{NULLIF}}}||Returns {{{NULL}}} if the first argument equals the
> second.||✔||✔||✔||✔||[https://github.com/django/django/pull/9543
> 9543]||
> ||||||||||||||= **Math** =||
> ||**Name**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
> ||{{{ABS}}}||Returns the absolute
> value.||✔||✔||✔||✔||[https://github.com/django/django/pull/9577
> 9577], [https://github.com/django/django/pull/9622 9622]||
> ||{{{ACOS}}}||Returns the
> arccosine.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{ASIN}}}||Returns the
> arcsine.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{ATAN}}}||Returns the
> arctangent.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{ATAN2}}}||Returns the arctangent of the two variables passed to
> it.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{CEILING}}}||Returns the smallest integer value that is not less than
> a numeric
> expression||✔||{{{CEIL}}}||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{COS}}}||Returns the cosine expressed in
> radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{COT}}}||Returns the
> cotangent.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{DEGREES}}}||Returns a numeric expression converted from radians to
> degrees.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{EXP}}}||Returns the base of the natural logarithm (e) raised to the
> power of a numeric
> expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{FLOOR}}}||Returns the largest integer value that is not greater than
> a numeric
> expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{LOG}}}||Returns the natural logarithm of a numeric
> expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{MOD}}}||Returns the remainder of one expression by diving by another
> expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{PI}}}||Returns the value of
> π||✔||-||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{POWER}}}||Returns the value of one expression raised to the power of
> another
> expression||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{RADIANS}}}||Returns the value of an expression converted from
> degrees to
> radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{ROUND}}}||Returns a numeric expression rounded to an integer.\\Can
> be used to round an expression to a number of decimal
> points||✔||✔||✔||✔||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{SIN}}}||Returns the sine given in
> radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{SQRT}}}||Returns the square
> root.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||{{{TAN}}}||Returns the tangent expressed in
> radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
> 9622]||
> ||||||||||||||= **Text** =||
> ||**Name**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
> ||{{{ASCII}}}||Returns numeric value of left-most character. (Equivalent
> to {{{ord()}}} in
> Python.)||✔||✔||✔||{{{UNICODE}}}||[https://github.com/django/django/pull/9583
> 9583]||
> ||{{{CHR}}}||Character with the given
> code||✔||✔||{{{CHAR}}}||{{{CHAR}}}||[https://github.com/django/django/pull/9583
> 9583]||
> ||{{{LEFT}}}||Returns the leftmost number of characters as
> specified||✔||✔**^2^**||✔||✔**^2^**||[https://github.com/django/django/pull/9583
> 9583]||
> ||{{{LPAD}}}||Returns the string argument, left-padded with the specified
> string||✔||✔||✔||-||[https://github.com/django/django/pull/9798
> 9798]||
> ||{{{LTRIM}}}||Removes leading
> spaces||✔||✔||✔||✔||[https://github.com/django/django/pull/9220
> 9220]||
> ||{{{MD5}}}||Calculates the MD5 hash of string, returning the result in
> hexadecimal||✔||-||-||✔**^1^**||-||
> ||{{{REPEAT}}}||Repeats a string the specified number of
> times||✔||-||✔||✔**^1^**||[https://github.com/django/django/pull/9808
> 9808]||
> ||{{{REPLACE}}}||Replaces occurrences of a specified
> string||✔||✔||✔||✔||[https://github.com/django/django/pull/9539 9539]
> [[span(style=font-size:75%, (Merged))]]||
> ||{{{REVERSE}}}||Reverse the characters in a
> string||✔||-||✔||✔**^1^**||-||
> ||{{{RIGHT}}}||Returns the specified rightmost number of
> characters||✔||✔**^2^**||✔||✔**^2^**||[https://github.com/django/django/pull/9583
> 9583]||
> ||{{{RPAD}}}||Appends string the specified number of
> times||✔||✔||✔||-||[https://github.com/django/django/pull/9798 9798]||
> ||{{{RTRIM}}}||Removes trailing
> spaces||✔||✔||✔||✔||[https://github.com/django/django/pull/9220
> 9220]||
> ||{{{TRIM}}}||Removes leading and trailing
> spaces||✔||✔||✔||✔||[https://github.com/django/django/pull/9220
> 9220]||
>
> - **^1^** Function can be easily supported on SQLite with a
> [https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.create_function
> user defined function].
> - **^2^** Behaviour can be emulated by using {{{SUBSTR}}}.
New description:
I was surprised to learn that we didn't have a StrIndex function until
version 2, and yet we had Substr since at least version 1.8. I wonder how
users were using Substr without also finding a use for StrIndex this whole
time. Anyway, since we seem to be adding these functions one at a time,
why don't we work on trying to get the built-ins implemented in one sweep
instead?
We may even want to split the documentation page
(https://docs.djangoproject.com/en/dev/ref/models/database-functions/)
into further categories with String functions and Numeric functions.
This is just a sample checklist, with corresponding attributes to which
backend has them available.
||||||||||||||||= **Comparison** =||
||**Django**||**SQL**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
||{{{NullIf}}}||{{{NULLIF}}}||Returns {{{NULL}}} if the first argument
equals the
second.||✔||✔||✔||✔||[https://github.com/django/django/pull/9543
9543]||
||||||||||||||||= **Math** =||
||**Django**||**SQL**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
||{{{Abs}}}||{{{ABS}}}||Returns the absolute
value.||✔||✔||✔||✔||[https://github.com/django/django/pull/9622
9622]||
||{{{ACos}}}||{{{ACOS}}}||Returns the
arccosine.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{ASin}}}||{{{ASIN}}}||Returns the
arcsine.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{ATan}}}||{{{ATAN}}}||Returns the
arctangent.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{ATan2}}}||{{{ATAN2}}}||Returns the arctangent of the two variables
passed to
it.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Ceil}}}||{{{CEILING}}}||Returns the smallest integer value that is
not less than a numeric
expression||✔||{{{CEIL}}}||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Cos}}}||{{{COS}}}||Returns the cosine expressed in
radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Cot}}}||{{{COT}}}||Returns the
cotangent.||✔||✔**^5^**||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Degrees}}}||{{{DEGREES}}}||Returns a numeric expression converted
from radians to
degrees.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Exp}}}||{{{EXP}}}||Returns the base of the natural logarithm (e)
raised to the power of a numeric
expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Floor}}}||{{{FLOOR}}}||Returns the largest integer value that is not
greater than a numeric
expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Ln}}}||{{{LN}}}||Returns the natural logarithm of a numeric
expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Log}}}||{{{LOG(B, X)}}}||Returns the logarithm of a numeric
expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Mod}}}||{{{MOD}}}||Returns the remainder of one expression by diving
by another
expression.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Pi}}}||{{{PI}}}||Returns the value of
π||✔||✔**^4^**||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Power}}}||{{{POWER}}}||Returns the value of one expression raised to
the power of another
expression||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Radians}}}||{{{RADIANS}}}||Returns the value of an expression
converted from degrees to
radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Round}}}||{{{ROUND}}}||Returns a numeric expression rounded to an
integer.\\Can be used to round an expression to a number of decimal
points||✔||✔||✔||✔||[https://github.com/django/django/pull/9622
9622]||
||{{{Sin}}}||{{{SIN}}}||Returns the sine given in
radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Sqrt}}}||{{{SQRT}}}||Returns the square
root.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||{{{Tan}}}||{{{TAN}}}||Returns the tangent expressed in
radians.||✔||✔||✔||✔**^1^**||[https://github.com/django/django/pull/9622
9622]||
||||||||||||||||= **Text** =||
||**Django**||**SQL**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**||
||{{{Ord}}}||{{{ASCII}}}||Returns numeric value of left-most character.
(Equivalent to {{{ord()}}} in
Python.)||✔||✔||✔||{{{UNICODE}}}||~~9583~~||
||{{{Chr}}}||{{{CHR}}}||Character with the given
code||✔||✔||{{{CHAR}}}||{{{CHAR}}}||~~9583~~||
||{{{Left}}}||{{{LEFT}}}||Returns the leftmost number of characters as
specified||✔||✔**^2^**||✔||✔**^2^**||~~9583~~||
||{{{LPad}}}||{{{LPAD}}}||Returns the string argument, left-padded with
the specified string||✔||✔||✔||✔**^1^**||~~9798~~||
||{{{LTrim}}}||{{{LTRIM}}}||Removes leading
spaces||✔||✔||✔||✔||~~9220~~||
||{{{MD5}}}||{{{MD5}}}||Calculates the MD5 hash of string, returning the
result in hexadecimal||✔||-||-||✔**^1^**||-||
||{{{Repeat}}}||{{{REPEAT}}}||Repeats a string the specified number of
times||✔||✔**^3^**||✔||✔**^1^**||[https://github.com/django/django/pull/9808
9808]||
||{{{Replace}}}||{{{REPLACE}}}||Replaces occurrences of a specified
string||✔||✔||✔||✔||~~9539~~||
||{{{Reverse}}}||{{{REVERSE}}}||Reverse the characters in a
string||✔||-||✔||✔**^1^**||-||
||{{{Right}}}||{{{RIGHT}}}||Returns the specified rightmost number of
characters||✔||✔**^2^**||✔||✔**^2^**||~~9583~~||
||{{{RPad}}}||{{{RPAD}}}||Appends string the specified number of
times||✔||✔||✔||✔**^1^**||~~9798~~||
||{{{RTrim}}}||{{{RTRIM}}}||Removes trailing
spaces||✔||✔||✔||✔||~~9220~~||
||{{{Trim}}}||{{{TRIM}}}||Removes leading and trailing
spaces||✔||✔||✔||✔||~~9220~~||
- **^1^** Function can be easily supported on SQLite with a
[https://docs.python.org/3/library/sqlite3.html#sqlite3.Connection.create_function
user defined function].
- **^2^** Behaviour can be emulated by using {{{SUBSTR}}}.
- **^3^** Behaviour can be emulated by using {{{LENGTH}}} and {{{RPAD}}}.
- **^4^** Behaviour can be emulated by directly substituting constant
{{{math.pi}}}.
- **^5^** Behaviour can be emulated by using {{{1 / TAN(X)}}}.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/28643#comment:38>
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