[Zope-Moz] Re: [Zope] RDF Use cases

[Shalabh Chaturvedi]

Hi Martijn,

Thanks for the explanation. It has made things a lot clearer. I think I
had missed the line between the RDF data model and XML(serialization).

> SC> Also, why not have the Zope Studio also query and manipulate the
Zope
> SC> objects through RDF only (vs having some other interface).
>
> Because we want to keep Zope as open as possible. RDF would be one way
> of representing Zope data. WebDAV another. XML-RPC is one way of
> manipulating Zope, SOAP another.

I didn't mean to say that Zope stop supporting other standards, but that
the _Zope_Studio_ that's being designed use the Zope RDF model to
manipulate the Zope installation. This is the way it's going already (it
seems) which makes the suggestion redundant.

> But we can pull the RDF into Mozilla, and Mozilla allows you to query
> the RDF datamodel, and manipulate it. With XUL, the cross-platform
> user interface modeling language implemented in Mozilla, we can then
> display the data in the RDF, and allow a user to interact with it.
> Changes to the RDF datamodel can be detected, and then we can act upon
> those changes, by for example sending an XML-RPC call to the Zope
> server. This could be a way of implementing Visual Zope. We will
> however, think about how we would propagate changes in Zope (by other
> users or processes), into the datamodel in the browser.

I looked at the mozilla interfaces for RDF and am beginning to see where
all this is headed. The bits are slowly falling into place and I need to
read a lot more now.

> XML-RPC is one way of
> manipulating Zope, SOAP another.

From what I know, SOAP is a sort of specialized XML-RPC. So if Zope will
support SOAP, it will support XML-RPC too?

Thanks,
~Shalabh

----- Original Message -----
From: Martijn Pieters <mj@digicool.com>
To: Shalabh Chaturvedi <shalabh@pspl.co.in>
Cc: <zope-mozilla@zope.org>
Sent: Monday, December 20, 1999 1:06 PM
Subject: Re: [Zope-Moz] Re: [Zope] RDF Use cases


> Hello Shalabh,
>
> Monday, December 20, 1999, 6:08:41 AM, you wrote:
> SC> If I understand correctly this means we put the attributes of all
the
> SC> objects as RDF 'properties'. For eg: the object-type('DTMLDoc',
> SC> 'DTMLMethod', 'Folder' etc) becomes a property, and also
everything in
> SC> in Properties tab becomes an RDF property. If you meant something
else
> SC> then here's another Use Case ;-)
> SC> So, we have a bunch of XML (RDF) documents for all the Zope
objects.
> SC> These don't live as documents but probably get created on  the fly
from
> SC> the info in the ZODB. Does the RDF spec also define a way to
> SC> _manipulate_ the RDF statements, like you suggest?
>
> Let me try and give you a short explanation of what RDF is and what it
> can do.
>
> RDF is indeed a standard for describing metadata. So you can say that
> you have a resource, an object (the "subject", in RDF jargon), and
> this object has a property (the "predicate"), and this property has a
> value (the "object"). The value can be either another resource, or a
> literal value. In RDF this is depicted either by a triple ({pred,
> subj, obj}), or by a directed graph (watch it, ASCII art):
>
>
>    .-~~~~~-.  predicate   +--------+
>   | subject |------------>| object |
>    ~._____.~              +--------+
>
> With this datamodel, you can describe very complex structures,
> including an OODB. The subject can be anything that has a URI (URLs
> are a type of URI), so a Zope object will do fine. The subject could
> be http://www.zope.org/, the predicate RDF:type, and the object
> http://www.zope.org/Resources/ZopeRDFSchema#Application. With
> additional graphs, we can then also say what Zope properties are
> defined on the object, what security settings it has, and what
> subobjects it contains. And with a properly thought out Schema, we can
> also declare what classes Application inherits from.
>
> This RDF datamodel can then be serialized in XML. XML is the default
> serialization syntax, but not the only one. The RDF Recommendation
> only describes the datamodel, not how to manipulate it, or how to
> propagate changes in the RDF model back to Zope.
>
> But we can pull the RDF into Mozilla, and Mozilla allows you to query
> the RDF datamodel, and manipulate it. With XUL, the cross-platform
> user interface modeling language implemented in Mozilla, we can then
> display the data in the RDF, and allow a user to interact with it.
> Changes to the RDF datamodel can be detected, and then we can act upon
> those changes, by for example sending an XML-RPC call to the Zope
> server. This could be a way of implementing Visual Zope. We will
> however, think about how we would propagate changes in Zope (by other
> users or processes), into the datamodel in the browser.
>
> The above description of the use of RDF in Zope is but one example,
> albeit an extensive and far reaching one. Zope would not actually be
> "doing" any RDF, it would only generate XML to represent a RDF
> datamodel.
>
> But maybe you can think of a scenario where it would be beneficial for
> Zope to actually be able to directly manipulate a RDF datasource, to
> aggregate different sources into one model, and then query this model
> for internal purposes.
>
> SC> Also, why not have the Zope Studio also query and manipulate the
Zope
> SC> objects through RDF only (vs having some other interface).
>
> Because we want to keep Zope as open as possible. RDF would be one way
> of representing Zope data. WebDAV another. XML-RPC is one way of
> manipulating Zope, SOAP another.
>
> --
> Best regards,
>  Martijn Pieters                  mailto:mj@digicool.com
>
>
>
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