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From "Daniel John Debrunner (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-3290) Derby cannot store java Double or Float values .NaN and .[POSITIVE|NEGATIVE]_INFINITY
Date Wed, 19 Dec 2007 16:22:43 GMT

    [ https://issues.apache.org/jira/browse/DERBY-3290?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12553393
] 

Daniel John Debrunner commented on DERBY-3290:
----------------------------------------------

Just to add this is more involved than just removing the checks for Nan/Infinity. It needs
to be thought out otherwise one can end up with a whole host of bugs (as I think the user
thread pointed out for older versions of SQL Server). Examples of areas that require thought/work
are:

  - define how =,<,> work (most likely based upon IEEE)
  - define how +,-,*,/ work (most likely based upon IEEE)
  - does the decisions for <,> make sense for an index, where would Nan be ordered in
an index?
  - probably need to add builtin SQL functions for Double.isNan, isInfinite
  - how do aggregates work
     - does max() return positive infiinty if the column has that value, or does it throw
an exception or ignore the value
     - sum() with infinities, sum() with Nan - what happens ...
     - etc.
   - are literals needed for these values?
   - conversion to other numeric types

My vague memory is that these values are not accepted in Derby to avoid all of these issues.

I'm not sure about the argument that because Java supports these values the database must,
as a counter example Java supports unicode strings but it would
be valid for a database to only support a character set that is a subset of unicode, thus
not supporting all of the character values that are valid in java.

> Derby cannot store java Double or Float values .NaN and .[POSITIVE|NEGATIVE]_INFINITY
> -------------------------------------------------------------------------------------
>
>                 Key: DERBY-3290
>                 URL: https://issues.apache.org/jira/browse/DERBY-3290
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>            Reporter: Thomas Nielsen
>            Priority: Minor
>         Attachments: TestNaN.java
>
>
> Issue originally reported on derby-user, where user cannot store .NaN or .INFINITE for
java datatypes Double or Float.

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