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RE: Invitation to contribute examples

From: Tomayko, Ryan <Ryan_Tomayko@stercomm.com>
Date: Thu, 10 Jan 2002 10:07:47 -0500
Message-ID: <5FD6397E455FD4118BAE00062938354002C90281@scidubmsg02.isg.stercomm.com>
To: "'Roland Merrick'" <roland_merrick@uk.ibm.com>, Jérôme Nègre <jerome.negre@e-xmlmedia.fr>
Cc: Steven Pemberton <steven.pemberton@cwi.nl>, www-forms@w3.org

> What I want to clearly understand is whether people really want multiple
> models which can refer to each other or whether this is an attempt to work
> around an XForms restriction which could be solved in other ways. 

I for one do not feel that it's an XForms restriction at all. I think it's
great design, with a missing piece. The ability to have multiple models and
specify where each should be pulled from is a great feature. I think what
you're proposing is to move the problem of cross-referencing instances from
the XForms level to the back end level (i.e. How would the documents get
combined into a single instance?). Also, combining documents into a single
instance would wreak havoc on the schema piece as now two or more documents,
with varying structure and purpose would have to be handled by a single
schema. This seems more of a kludge than to allow model cross referencing.

The multi-model paradigm works nicely. You can separate instances and their
respected schema as well as binding constraints. IMO, all that is needed is
a way for binding constraints in one model to reference instance documents
in another model. Micah's model() XPath function seems to fit perfectly for
this.

To clearly state my position and answer your question, I really want
multiple models which can refer to each other. 

Thanks,
-Ryan

-----Original Message-----
From: Roland Merrick [mailto:roland_merrick@uk.ibm.com]
Sent: Thursday, January 10, 2002 7:53 AM
To: Jérôme Nègre
Cc: Steven Pemberton; www-forms@w3.org
Subject: Re: Invitation to contribute examples



Greetings, I did not mean to imply that people's comments are not welcome,
on the contrary they are most welcome. What I was referring to was a thread
that was exploring the difficulties that arose as a result of the
restriction that one model cannot refer to another.

This restriction does exist and it does restrict some of the things that
people would like to achieve. My note was simply pointing out that a subset
of those problems can be addressed by the additional feature added to
<submitInfo> which allows an subset of an instance to be submitted.

Scenarios such as you have described below do actually exist though other
solutions could be devised. For example, XFORMS could be modified to allow
a set of external documents to be concatenated into an instance, or
non-XForms but still XML based solutions such as XInclude could play a
part.

What I want to clearly understand is whether people really want multiple
models which can refer to each other or whether this is an attempt to work
around an XForms restriction which could be solved in other ways. What your
example points out is a situation where I could create a single
model/instance if I was prepared/able to place all the content inline, but
I cannot achieve the same effect if some or all of the content is to be
sourced from a separate document or documents.

Regards, Roland
Ease of Use Strategy
Tel: +44 (0)1926-465440,   Fax: +44 (0)1926-465323, Mobile:  +44
(0)773-0300-937
Internet: Roland_Merrick@uk.ibm.com
Ease of Use:     http://www.ibm.com/easy/           http://w3.ibm.com/easy/


 

                    Jérôme Nègre

                    <jerome.negre@e-xm       To:     Roland
Merrick/UK/IBM@IBMGB                            
                    lmedia.fr>               cc:     "Steven Pemberton"
<steven.pemberton@cwi.nl>,          
                                              <www-forms@w3.org>

                    10/01/2002 12:11         Subject:     Re: Invitation to
contribute examples             
 

 

 





> Greetings, things are not as bad as people seem to be implying here.

I wonder who you're talking about ?
I have a few remarks on the *draft*, so I'm saying them. Once it'll be a
recommendation, it'll be too late.

<snip>
> I know this doesn't fix the cross model issue that you have recognised
but
> is does reduce the number of practical, rather than theoretical,
situations
> where the form designer might have had to resort to two models.

In my example, everything was inline and made simple to be concise.
Let's go for a real-life, pratical example. I hope you'll like it.

Let's say I'm running an e-commerce site.
I have a XML catalog at http://mysite.com/catalog.xml.
Since my customers can save their basket between sessions, the current
basket of a customer is available at http://mysite.com/basket.xml
(identification being made with the help of cookies or whatever).
Of course, my form needs some working variables.
I might end up with something like that:

<html>
 <head>
  <xform:model id="catalog">
   <xform:instance xlink:href="http://mysite.com/catalog.xml"/>
...
  <xform:model id="basket">
   <xform:instance xlink:href="http://mysite.com/basket.xml"/>
...
  <xform:model id="working_variables">
   <xform:instance>
    ...
   </xform:instance>
...
</html>

So, this is a practical situation, how do you rewrite it with only one
model
? Of course, it isn't allowed to write a server-side script, you must use
pure XForms.

Regards,
Jérôme
Received on Thursday, 10 January 2002 10:10:39 GMT

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