#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 felixxm:
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||✔||✔||✔||-||-||
> ||{{{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||✔||-||✔||-||-||
> ||{{{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||✔||✔||✔||-||-||
> ||{{{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** =||
||**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||✔||-||✔||-||-||
||{{{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}}}.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/28643#comment:35>
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