#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:  0                    |      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.  There are probably several more that I
> have missed.  These functions are available directly out of the box with
> PostgreSQL.
>
> String functions not yet implemented:
> ASCII(): Returns numeric value of left-most character
> CHR(): Character with the given code.
> LEFT(): Returns the leftmost number of characters as specified
> LPAD(): Returns the string argument, left-padded with the specified
> string
> LTRIM(): Removes leading spaces
> MD5(): Calculates the MD5 hash of string, returning the result in
> hexadecimal
> REPEAT(): Repeats a string the specified number of times
> REPLACE(): Replaces occurrences of a specified string
> REVERSE(): Reverse the characters in a string
> RIGHT(): Returns the specified rightmost number of characters
> RPAD(): Appends string the specified number of times
> RTRIM(): Removes trailing spaces
> TRIM(): Removes leading and trailing spaces
>
> Numeric functions:
> ABS(): Returns the absolute value.
> ACOS(): Returns the arccosine.
> ASIN(): Returns the arcsine.
> ATAN(): Returns the arctangent.
> ATAN2(): Returns the arctangent of the two variables passed to it.
> CEILING(): Returns the smallest integer value that is not less than a
> numeric expression
> COS(): Returns the cosine expressed in radians.
> COT(): Returns the cotangent.
> DEGREES(): Returns a numeric expression converted from radians to
> degrees.
> EXP(): Returns the base of the natural logarithm (e) raised to the power
> of a numeric expression.
> FLOOR(): Returns the largest integer value that is not greater than a
> numeric expression.
> LOG(): Returns the natural logarithm of a numeric expression.
> MOD(): Returns the remainder of one expression by diving by another
> expression.
> PI(): Returns the value of pi
> POWER(): Returns the value of one expression raised to the power of
> another expression
> RADIANS(): Returns the value of an expression converted from degrees to
> radians.
> ROUND(): Returns a numeric expression rounded to an integer. Can be used
> to round an expression to a number of decimal points
> SIN(): Returns the sine given in radians.
> SQRT(): Returns the square root.
> TAN(): Returns the tangent expressed in radians.

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.  There are probably several more that I
 have missed.  These functions are available directly out of the box with
 PostgreSQL.

 String functions not yet implemented:
 ASCII(): Returns numeric value of left-most character
 CHR(): Character with the given code.
 LEFT(): Returns the leftmost number of characters as specified
 LPAD(): Returns the string argument, left-padded with the specified string
 MD5(): Calculates the MD5 hash of string, returning the result in
 hexadecimal
 REPEAT(): Repeats a string the specified number of times
 REPLACE(): Replaces occurrences of a specified string
 REVERSE(): Reverse the characters in a string
 RIGHT(): Returns the specified rightmost number of characters
 RPAD(): Appends string the specified number of times
 LTRIM(): Removes leading spaces
 ([https://github.com/django/django/pull/9220 PR #9220])
 RTRIM(): Removes trailing spaces
 ([https://github.com/django/django/pull/9220 PR #9220])
 TRIM(): Removes leading and trailing spaces
 ([https://github.com/django/django/pull/9220 PR #9220])

 Numeric functions:
 ABS(): Returns the absolute value.
 ACOS(): Returns the arccosine.
 ASIN(): Returns the arcsine.
 ATAN(): Returns the arctangent.
 ATAN2(): Returns the arctangent of the two variables passed to it.
 CEILING(): Returns the smallest integer value that is not less than a
 numeric expression
 COS(): Returns the cosine expressed in radians.
 COT(): Returns the cotangent.
 DEGREES(): Returns a numeric expression converted from radians to degrees.
 EXP(): Returns the base of the natural logarithm (e) raised to the power
 of a numeric expression.
 FLOOR(): Returns the largest integer value that is not greater than a
 numeric expression.
 LOG(): Returns the natural logarithm of a numeric expression.
 MOD(): Returns the remainder of one expression by diving by another
 expression.
 PI(): Returns the value of pi
 POWER(): Returns the value of one expression raised to the power of
 another expression
 RADIANS(): Returns the value of an expression converted from degrees to
 radians.
 ROUND(): Returns a numeric expression rounded to an integer. Can be used
 to round an expression to a number of decimal points
 SIN(): Returns the sine given in radians.
 SQRT(): Returns the square root.
 TAN(): Returns the tangent expressed in radians.

--

-- 
Ticket URL: <https://code.djangoproject.com/ticket/28643#comment:8>
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