W3C home > Mailing lists > Public > www-forms@w3.org > March 2001

Re: Fw: XForms requirements

From: Berin Loritsch <bloritsch@apache.org>
Date: Mon, 26 Mar 2001 09:25:35 -0500
Message-ID: <3ABF515F.45A3EC19@apache.org>
To: XForms Mailing List <www-forms@w3.org>
Michael Friedman wrote:
> 
> With Micah's permission I'm posting this to the list.
> 
> Quick summary:
> 
> My concern is that the requirements do not make clear whether the objective
> is to do a better job of handling forms of the type that are currently done
> on the web and marginally increase the complexity and power of the forms we
> can use or if the objective is to let people build powerful and complex
> forms with tight database integrations like the ones people build with
> Oracle Developer, PowerBuilder, etc.

It appears to me that XForms is trying to provide a pure XML MVC (Model View
Controller) pattern.  That means that you have the XForms Model (The model
portion), XForms DCL and processor (the controller), XForms UI (the view).

The separation of the Model and the Controller has alot of overlap, and I am
not that crazy about that part.  The "richness" of the XForms UI section
leaves alot of things missing--I think part of the design.  The reason is that
they are trying to cater to the smallest subset available (wireless devices).
The Model describes XML schema and dynamic constraints/calculated fields
for a data instance.  The instance is XML that conforms to the XForms Schema.

It is up to you to bind the instance to a real datasource.  That is one of the
major shortcommings of XForms.  The other is that it assumes that the prefered
method of dealing with XForms is through a DOM.

> My concern is that the need is for the latter, but the requirements cater
> more to the former.

The requirements are still young.  You also have to keep in mind that Database
integration is only one type of data binding.  What about mapping to EJBs or
CORBA objects?  There are other standards that deal with that mapping.  I am
looking at a public domain one that maps XML to a DBMS.

That is also part of the limitation with the XForms Model.  The Model assumes
nothing other than XML integration.  What is needed is a standard binding language
that will conform XML to an arbitrary backend--whether it is object based or
table based.  I have not looked at XBL (XML Binding Language) yet, but it could
possibly fill this void.

> I would really appreciate it if some of the people involved in the standard
> could look at some of the more complex forms in the client/server versions
> of Oracle Financials, Peoplesoft, or SAP and ask themselves if XForms can be
> used to duplicate that functionality with a reasonable effort.

If you are talking about rich form controls that you would normally get with
an application setting, I am not sure how that would be approached.  You would
almost need a conformance level: embedded devices have to enable the core set
of UI controls, browser enabled deveices may have to enable a few more, and
lastly, stand alone applications would have to enable yet another set.

I don't know how desirable that is.  Maybe we could take a look at how many
distinct UI controls there are in use in today's GUIs.  The XForms spec makes
reference to a few more, but they have not been worked out as of the writing of
the spec.
Received on Monday, 26 March 2001 09:28:12 GMT

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