#28643: Complete the ORM Function Library -------------------------------------+------------------------------------- Reporter: Matthew Pava | Owner: Nick Pope 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, 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.||✔||✔||✔||✔||~~9543~~|| > ||||||||||||||||= **Math** =|| > ||**Django**||**SQL**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**|| > ||`Abs`||`ABS`||Returns the absolute value.||✔||✔||✔||✔||~~9622~~|| > ||`ACos`||`ACOS`||Returns the > arccosine.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`ASin`||`ASIN`||Returns the arcsine.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`ATan`||`ATAN`||Returns the > arctangent.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`ATan2`||`ATAN2`||Returns the arctangent of the two variables passed to > it.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Ceil`||`CEILING`||Returns the smallest integer value that is not less > than a numeric expression||✔||`CEIL`||✔||✔**^1^**||~~9622~~|| > ||`Cos`||`COS`||Returns the cosine expressed in > radians.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Cot`||`COT`||Returns the > cotangent.||✔||✔**^5^**||✔||✔**^1^**||~~9622~~|| > ||`Degrees`||`DEGREES`||Returns a numeric expression converted from > radians to degrees.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Exp`||`EXP`||Returns the base of the natural logarithm (e) raised to > the power of a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Floor`||`FLOOR`||Returns the largest integer value that is not greater > than a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Ln`||`LN`||Returns the natural logarithm of a numeric > expression.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Log`||`LOG(B, X)`||Returns the logarithm of a numeric > expression.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Mod`||`MOD`||Returns the remainder of one expression by diving by > another expression.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Pi`||`PI`||Returns the value of > π||✔||✔**^4^**||✔||✔**^1^**||~~9622~~|| > ||`Power`||`POWER`||Returns the value of one expression raised to the > power of another expression||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Radians`||`RADIANS`||Returns the value of an expression converted from > degrees to radians.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Round`||`ROUND`||Returns a numeric expression rounded to an > integer.\\Can be used to round an expression to a number of decimal > points||✔||✔||✔||✔||~~9622~~|| > ||`Sin`||`SIN`||Returns the sine given in > radians.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Sqrt`||`SQRT`||Returns the square > root.||✔||✔||✔||✔**^1^**||~~9622~~|| > ||`Tan`||`TAN`||Returns the tangent expressed in > radians.||✔||✔||✔||✔**^1^**||~~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, 6^**||✔||✔**^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^**||~~9808~~|| > ||`Replace`||`REPLACE`||Replaces occurrences of a specified > string||✔||✔**^6^**||✔||✔||~~9539~~|| > ||`Reverse`||`REVERSE`||Reverse the characters in a string||✔||✔**^6, > 7^**||✔||✔**^1^**||~~10827~~|| > ||`Right`||`RIGHT`||Returns the specified rightmost number of > characters||✔||✔**^2^**||✔||✔**^2^**||~~9583~~|| > ||`RPad`||`RPAD`||Appends string the specified number of > times||✔||✔**^6^**||✔||✔**^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^** Can be emulated by using `SUBSTR`. > - **^3^** Can be emulated by using `LENGTH` and `RPAD`. > - **^4^** Can be emulated by directly substituting constant `math.pi`. > - **^5^** Can be emulated by using `1 / TAN(X)`. > - **^6^** Doesn't work properly with multibyte characters sets on Oracle. > - **^7^** The `REVERSE` function is undocumented on Oracle. 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.||✔||✔||✔||✔||~~9543~~|| ||||||||||||||||= **Math** =|| ||**Django**||**SQL**||**Description**||**PostgreSQL**||**Oracle**||**MySQL**||**SQLite**||**PR**|| ||`Abs`||`ABS`||Returns the absolute value.||✔||✔||✔||✔||~~9622~~|| ||`ACos`||`ACOS`||Returns the arccosine.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`ASin`||`ASIN`||Returns the arcsine.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`ATan`||`ATAN`||Returns the arctangent.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`ATan2`||`ATAN2`||Returns the arctangent of the two variables passed to it.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Ceil`||`CEILING`||Returns the smallest integer value that is not less than a numeric expression||✔||`CEIL`||✔||✔**^1^**||~~9622~~|| ||`Cos`||`COS`||Returns the cosine expressed in radians.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Cot`||`COT`||Returns the cotangent.||✔||✔**^5^**||✔||✔**^1^**||~~9622~~|| ||`Degrees`||`DEGREES`||Returns a numeric expression converted from radians to degrees.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Exp`||`EXP`||Returns the base of the natural logarithm (e) raised to the power of a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Floor`||`FLOOR`||Returns the largest integer value that is not greater than a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Ln`||`LN`||Returns the natural logarithm of a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Log`||`LOG(B, X)`||Returns the logarithm of a numeric expression.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Mod`||`MOD`||Returns the remainder of one expression by diving by another expression.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Pi`||`PI`||Returns the value of π||✔||✔**^4^**||✔||✔**^1^**||~~9622~~|| ||`Power`||`POWER`||Returns the value of one expression raised to the power of another expression||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Radians`||`RADIANS`||Returns the value of an expression converted from degrees to radians.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Round`||`ROUND`||Returns a numeric expression rounded to an integer.\\Can be used to round an expression to a number of decimal points||✔||✔||✔||✔||~~9622~~|| ||`Sin`||`SIN`||Returns the sine given in radians.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Sqrt`||`SQRT`||Returns the square root.||✔||✔||✔||✔**^1^**||~~9622~~|| ||`Tan`||`TAN`||Returns the tangent expressed in radians.||✔||✔||✔||✔**^1^**||~~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, 6^**||✔||✔**^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||✔||✔**^8^**||✔||✔**^1^**||-|| ||`Repeat`||`REPEAT`||Repeats a string the specified number of times||✔||✔**^3^**||✔||✔**^1^**||~~9808~~|| ||`Replace`||`REPLACE`||Replaces occurrences of a specified string||✔||✔**^6^**||✔||✔||~~9539~~|| ||`Reverse`||`REVERSE`||Reverse the characters in a string||✔||✔**^6, 7^**||✔||✔**^1^**||~~10827~~|| ||`Right`||`RIGHT`||Returns the specified rightmost number of characters||✔||✔**^2^**||✔||✔**^2^**||~~9583~~|| ||`RPad`||`RPAD`||Appends string the specified number of times||✔||✔**^6^**||✔||✔**^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^** Can be emulated by using `SUBSTR`. - **^3^** Can be emulated by using `LENGTH` and `RPAD`. - **^4^** Can be emulated by directly substituting constant `math.pi`. - **^5^** Can be emulated by using `1 / TAN(X)`. - **^6^** Doesn't work properly with multibyte characters sets on Oracle. - **^7^** The `REVERSE` function is undocumented on Oracle. - **^8^** Can be supported by using `STANDARD_HASH` on Oracle. -- -- Ticket URL: <https://code.djangoproject.com/ticket/28643#comment:58> Django <https://code.djangoproject.com/> The Web framework for perfectionists with deadlines. -- You received this message because you are subscribed to the Google Groups "Django updates" group. 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