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From Sylvain Wallez <sylv...@apache.org>
Subject Re: [RT] Direct Form->SQL mapping through OJB and DynaBeans
Date Fri, 31 Oct 2003 16:02:26 GMT
Marc Portier wrote:

> Sylvain Wallez wrote:
>
>> Hi,
>>
>> Some people to which I demonstrated Woody and Flowscript asked me how 
>> we can directly map forms to a database.
>
>
> no surprise here :-)
>
>> Yeah, I know that architecturally having intermediate domain objects 
>> is better, but it seems a bit overkill when what you need is just a 
>> simple CRUD front-end to a database and have no additional logic.
>>
>> Writing a SQL binding for forms seems a complicated beast to me 
>> (maybe I'm wrong as I'm not very fluent in SQL), so I was thinking of 
>> using tools that would to the dirty work for me.
>
>
> I have been thinking about the direct sql mapping on and off, the 
> biggest problem I was able to identify (not solve) is that sql is not 
> 'symmetric' in its load and save operations (while woody binding is)
>
> with symmetric I mean for doing updates or inserts you can't just give 
> a resultset back to the JDBC connection...


Yep. I hit to the same wall when thinking of this problem.

>> And here comes (Antonio, you'll be happy!!) OJB, which AFAIK can 
>> persist DynaBeans [1].
>>
>> So what about adding a getBean() to the widget interface that would 
>> return a DynaBean wrapper of the form widgets? A simple OJB mapping 
>> file and voilĂ , persistant forms!
>
>
> Wow.
> This would set asside the usage of the form.save(object) alltogether 
> then?


Yes, but only in the case of direct mapping to the database. The current 
binding has to be used when there's an application data model.

> I'm not into OJB enough to understand just how simple this simple 
> mapping file would be, some example/hint might help understanding the 
> usability...


Me neither, but I think this will be the itch that will make me scratch ;-)

>> What do you think?
>
>
> I think it would make for a killer usage pattern for the easy-apps!
>
> And it makes sense: the form-definition model is in fact to be seen as 
> a 'class' definition of form-instances, no?


Exactly.

> (maybe in stead of dynabeans you could abuse the opportunity to boost 
> your bcel skills again ;-))


Mmmpf... I don't want to introduce stuff I would be the only one to 
understand ;-)

And using DynaBeans should be fairly easy compared to writing a BCEL 
code generator. Note also that JXPath already handles DynaBeans, which 
would make navigating a form using XPath expressions a breeze!

Sylvain

-- 
Sylvain Wallez                                  Anyware Technologies
http://www.apache.org/~sylvain           http://www.anyware-tech.com
{ XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects }
Orixo, the opensource XML business alliance  -  http://www.orixo.com



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