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From "Craig L Russell (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (JDO-721) Specifying NULL elements positioning in ordered columns
Date Fri, 02 Aug 2013 16:51:49 GMT

     [ https://issues.apache.org/jira/browse/JDO-721?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Craig L Russell updated JDO-721:
--------------------------------

    Fix Version/s: JDO 3 maintenance release 2 (3.2)
    
> Specifying NULL elements positioning in ordered columns
> -------------------------------------------------------
>
>                 Key: JDO-721
>                 URL: https://issues.apache.org/jira/browse/JDO-721
>             Project: JDO
>          Issue Type: Improvement
>          Components: specification
>    Affects Versions: JDO 3 update 1 (3.0.1)
>            Reporter: Muhammad Gelbana
>            Priority: Minor
>              Labels: jdoql
>             Fix For: JDO 3 maintenance release 2 (3.2)
>
>
> I don't know about other RDBMS but in MySQL ordering, it's possible to specify whether
NULL column fields are placed in the beginning or at the end of the ordering, i.e.:
> ORDER BY `values_column` IS NULL DESC
> [values_column]
> NULL
> NULL
> value1
> value2
> value3
> or the other way around (ORDER BY `values_column` IS NULL ASC):
> [values_column]
> value1
> value2
> value3
> NULL
> NULL
> I checked JDO 3 specification and found that JDOQL's ordering specification doesn't support
specifying NULL values handling:
> ------------------------------------------------------------------------------
> 26.7 Ordering Specification
> This section describes the syntax of the setOrdering argument.
>     OrderingClause:
>         OrderingSpecs ,opt
>     OrderingSpecs:
>         OrderingSpec
>         OrderingSpecs , OrderingSpec
>     OrderingSpec:
>         Expression Ascending
>         Expression Descending
>     Ascending: one of
>         asc ascending
>     Descending: one of
>         desc descending
> Please note, as a usability feature OrderingClause supports an optional trailing comma.
> ------------------------------------------------------------------------------
> Thank you for your time and efforts.

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