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From "Maia Kozheva (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (OPENJPA-1991) Support ROW_NUMBER pagination on MS SQL Server 2005
Date Tue, 03 May 2011 07:22:03 GMT

     [ https://issues.apache.org/jira/browse/OPENJPA-1991?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Maia Kozheva updated OPENJPA-1991:
----------------------------------

    Attachment: SQLServer2005Dictionary.java

Attached is a custom class that we use in our project for this. It is based on existing code
in OpenJPA's OracleDictionary (which aliases joined columns for subselect), but adjusted to
the SQL Server syntax. It falls back to the TOP N syntax if the SQL Server version is too
low to support ROW_NUMBER, or if offset == 0.

> Support ROW_NUMBER pagination on MS SQL Server 2005
> ---------------------------------------------------
>
>                 Key: OPENJPA-1991
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-1991
>             Project: OpenJPA
>          Issue Type: Improvement
>          Components: jdbc
>    Affects Versions: 2.1.0
>            Reporter: Maia Kozheva
>         Attachments: SQLServer2005Dictionary.java
>
>
> The current implementation of SQLServerDictionary in OpenJPA only supports pagination
based on TOP (offset+limit), which fetches more rows than necessary and thus degrades performance
in comparison to DBMSes that support both limit and offset specification, like MySQL.
> SQL Server 2005 supports a ROW_NUMBER function that can be used to restrict the result
list to the necessary slice, taking both limit and offset into account. I would like OpenJPA
to support this syntax.

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