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From "Kevin Sutter" <kwsut...@gmail.com>
Subject Re: [jira] Created: (OPENJPA-240) Persistent field mappings to database supported XML columns
Date Mon, 21 May 2007 18:12:32 GMT
OpenJPA Community,
So, is this XML Mapping support interesting to the community?  Catalina has
been working on a solution for this O/Xml Mapping support and is looking for
interest from the community for discussion purposes before possibly
contributing it to OpenJPA.  We can provide more detail when asked.  But, in
a nutshell, here's the proposal...

We planned to use the JAXB support for doing the XML Mapping.  We wanted the
programming model to be as close to what is provided by JPA (and OpenJPA) as
possible.  That is, we were trying to keep the basic idea of O/R Mapping,
but apply it to O/XML Mapping.

With the XML column support, the embedded class would use XML marshaling to
write the data to XML columns and unmarshaling to retrieve the data
from XMLcolumns. The path expressions and predicates over the embedded
class is
converted to XML predicates and XPATH and/or XQuery expressions and pushed
down to database.

This pushdown would be accomplished by adding to and modifying the
DBDictionaries for DB2, Oracle, and SQL Server.  At this time, these are the
database players (that we know of) that provide the required level of
support.

A persistent property that maps to an XML column would be annotated by
@Persistent, @Column, and @Strategy.  The embedded classes would be
annotated with JAXB XML binding annotations. In addition, the class that
maps to the root of the XML document needs to be annotated by
@XmlRootElement.

@Strategy annotation requires a value handler to be specified for
XMLmarshaling and unmarshaling.
OpenJPA would provide a default XML Value Handler.  A customer could provide
their own XML value handler.

Comments and/or suggestions would be appreciated to kickstart this
activity.  Thanks!

Kevin


On 5/16/07, Catalina Wei (JIRA) <jira@apache.org> wrote:
>
> Persistent field mappings to database supported XML columns
> -----------------------------------------------------------
>
>                  Key: OPENJPA-240
>                  URL: https://issues.apache.org/jira/browse/OPENJPA-240
>              Project: OpenJPA
>           Issue Type: New Feature
>           Components: jdbc
>             Reporter: Catalina Wei
>
>
>
> Many database systems such as DB2 version 9, Oracle 10g, and SQLServer
> 2005 have support for XML column types. XML documents can be stored natively
> in the XML columns in the database.
> What is OpenJPA's position of supporting the XML columns ?
>
>
>
> --
> This message is automatically generated by JIRA.
> -
> You can reply to this email to add a comment to the issue online.
>
>

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