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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-3063) Extend the system function mechanism to support functions with multiple arguments
Date Mon, 10 Sep 2007 10:02:29 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3063?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12526118

Kristian Waagan commented on DERBY-3063:

I have two initial questions regarding this issue:
 a) Is it worth the extra code to support functions with more than one argument?
    - Support for one or two can be implemented using static final variables.
    - Support for an arbitrary number of arguments must be done by creating the needed structures
in a loop.
 b) Is it possible to get Derby to "automatically" allow for valid conversions?
     For instance, JDBC defines POWER(number, power) where 'power' is an integer. StrictMath
has pow(double,double). How do I get Derby to convert the integer 'power' to a 'double' when
passing the value to the Java function? (I'm in the context of system functions defined in
a table - see DERBY-475).

Question a) arises because right now I don't see many functions that actually requires more
than one argument (ATAN2 is one of them). Can these few functions easily be added and implemented
in a different way?

I'm attaching a sample patch adding support for functions with arbitrary number of arguments.
Optimizations can easily be done for the common case of one or two arguments.

> Extend the system function mechanism to support functions with multiple arguments
> ---------------------------------------------------------------------------------
>                 Key: DERBY-3063
>                 URL: https://issues.apache.org/jira/browse/DERBY-3063
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions:
>            Reporter: Kristian Waagan
>            Priority: Minor
> Extend the existing functionality for adding Java functions to SQL to support functions
with multiple arguments.

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