Hi Gianugo,
I haven't thought about adding namespaces, but it is probably a good
idea.
It a small change that has very little impact, but as you mention would open
up lots of possibilities. I'd like to get this first cut into the mainline
code base, then add features. But your suggestion will be high on my list.
Once you enable metadata, all new collections and documents will have a
metadata object associated with them. Collections and documents that
already exist will have metadata objects created for them when you request
it. The current implementation stores the creation time and last modified
time for you. We could add more, but I was think of a regular filesystem,
and these are two of the more beneficial features of filesystems.
I have not thought too much about the XML:DB API extensions. I
implemented
a few simple XML-RPC methods that allow users access to the metadata. My
understanding of "Service" in the context of Xindice is pretty limited. It
might be worthwhile to create a MetaDataService. However, I think simple
XML-RPC methods are simpler for now. Are there clear benefits to providing
a MetaDataService that are not available by simply using the XML-RPC
methods?
Thanks for taking the time to look at this feature! I personally think
it's pretty cool, and could help to differentiate Xindice from other XML
dbs.
Thanks
Dave Viner
-----Original Message-----
From: Gianugo Rabellino [mailto:[EMAIL PROTECTED]
Sent: Tuesday, November 26, 2002 1:13 AM
To: [EMAIL PROTECTED]
Subject: Re: first impl of metadata storage for xindice
Dave Viner wrote:
> Hi,
> For the past few weeks, I've been working on developing the meta
> data storage facility that we discussed long ago on the xindice-dev list.
> (See http://marc.theaimsgroup.com/?t=102873960400001&r=1&w=2 for
> discussion.)
Dave,
this is really cool stuff, thanks a lot for providing it.
I have to go through it a bit more to understand the implementation, but
as of now I have already some questions/suggestions floating around:
1. Have you thought about properly namespacing the metadata XML? Even a
default namespace it might be safer (think about "including" the
metadata in the data stream). I think this is an easy yet powerful
addition, and it might allow for cool stuff like embedding (namespaced)
metadata in a Collection or Resource result;
2. Do we have to explicitly set the metadata for any resource or, by
just enabling a collection-level metadata each resource will get a
minimum set such as creation/modification time? I understand that those
data are available in the Xindice core, so it should be fairly easy to
use them;
3. I'm thinking about how metadata might be exposed by a simple
extension of the XML:DB API. I think that the "Service" extension point
might be a good place to start (something like doing a
MetadataQueryService). Have you thought about it? I think that, while we
will have to go our way sooner or later, we should try to stay as close
as possible to the API.
Let me know what you think. Meanwhile, I'm eager to play with your
implementation! :-)
Ciao,
--
Gianugo Rabellino
