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https://issues.apache.org/jira/browse/OFBIZ-3740?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12865116#action_12865116
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Bob Morley commented on OFBIZ-3740:
-----------------------------------
Hi Divesh,
I added a more detailed description in the forum thread; but in brief this is a
generic solution which supports all databases which generates the sql
accordingly. What this patch does _not_ do is apply a standard default order
for all databases; it just adds support for one to dictate how they want the
nulls sorted.
For example, when one sets the order-by they can set it to "lastName DESC NULLS
FIRST" which should apply to all databases.
> Support for order by nulls first/last
> -------------------------------------
>
> Key: OFBIZ-3740
> URL: https://issues.apache.org/jira/browse/OFBIZ-3740
> Project: OFBiz
> Issue Type: Bug
> Components: framework
> Affects Versions: SVN trunk
> Reporter: Bob Morley
> Priority: Minor
> Fix For: SVN trunk
>
> Attachments: OFBIZ-3740_SupportOrderByNulls.patch
>
>
> This patch provides the fundamentals to resolve an issue where the sorting of
> null values were inconsistent (sometimes sorting first and other times
> sorting last). Specifically, this patch allows one to create an order-by
> clause via any of the order-by elements of "-myField NULLS LAST" where this
> text parses out the - (as descending) and the "nulls last".
> Since not all databases support the "nulls" argument on an order by clause
> (it was introduced as part of the OLAP support specification) , our
> entity-engine.xml file allows each data source to indicate if it has this
> support. If the support does not exist and nulls first/last is specified,
> the sql that is generated uses native sql to simulate the nulls first/last
> intent. At this time, the derby, postgres, and oracle databases are marked
> to use the nulls first grammar.
> Right now, if you do not specify "NULLS XXX" in the field-name for the
> order-by it makes no change whatsever (naturally this assumption could be
> changed to have a default).
> It should be noted, that my intent here was ultimately to "properly" model
> the order by into something whose xml representation could look something
> like ...
> <entity-order-by field-name="fieldName" ascending="true" nulls-first="true" />
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