Re: [eclipselink-users] [OT]-ish Reading Annotation Data

[Tim Hollosy <hollosyt@xxxxxxxxx>]

The idea of having a POJO based entity layer like we have in JPA is
that those same entities that you define once for JPA can and should
be used for other things -- like holding form values in a web
framework, etc.

./tch



On Tue, Sep 29, 2009 at 6:41 AM, RogerV <roger.varley@xxxxxxxxxxxxxx> wrote:
>
>
>
> mobrien wrote:
>>
>> We welcome any suggestions on extending the JPA 2.0 API implementation.
>> I will add extended annotation access to the design page at
>> http://wiki.eclipse.org/EclipseLink/Development/JPA_2.0/metamodel_api
>>
>
> Hi Michael
>
> I'm coming from being a long term developer on IBM S/38's, AS/400's and
> latterly on SAP R/3 systems. These systems all had a "meta layer" that sat
> between the application and the database - a definition repository or a data
> dictionary if you like. This allowed you to define your data elements once
> and once only. So you could define your customer number for example as a 9
> digit integer field. You could then define other fields in terms of them
> being a "Customer Number" type. Not only could you define the type & size,
> you could set default values, display/print formatting rules, text that
> would be used as labels when displaying/printing, text that would be used as
> help text (tooltips would, I guess, be the java equivalent). The
> "disadvantage" I see with JPA & Java, at the moment is that this information
> (for example element length) is often defined in multiple locations - it's
> in the DB table definitions, it's in the entity annotation, it's in the
> validation code/framework and it's often in the html/css definitions as
> well.
>
> So I'm wondering if the idea of a "data dictionary" would be of more use.
> I've no idea whether this concept would be a welcome addition to
> EclipseLink, or even if it's physically possible.  All I can say having used
> such systems, that it brings consistancy to displays and reports, eliminates
> definition duplication, makes data changes simple to implement application
> wide and generally makes life easier.
>
>
>
> Regards
>
>
>
> --
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>
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