[Xesam] Metadata Storage Daemon
phreedom.stdin at gmail.com
Tue Jan 15 07:37:29 PST 2008
В сообщении от Tuesday 15 January 2008 17:05:35 Jamie McCracken написал(а):
> On Tue, 2008-01-15 at 15:51 +0100, Sebastian Trüg wrote:
> > On Saturday 12 January 2008 00:05:38 Mikkel Kamstrup Erlandsen wrote:
> > > On 11/01/2008, Sebastian Trüg <strueg at mandriva.com> wrote:
> > > > Just my 2 cents:
> > > > Soprano has a IMOH very good DBus API  for RDF storage which
> > > > fulfills all 3 of your requirements below. We already use it for
> > > > Nepomuk and it works great. And since Xesam is already using URIs to
> > > > identify stuff why not go the extra mile to RDF storage altogether?
> > >
> > > I thought Soprano depended on Qt?
> > That has nothing to do with the D-Bus interface. I thought we were
> > looking for an API?
> > > Anyways, I don't think the RDF quadruples is a good thing to expose
> > > directly to the programmers who just want a quick and dirty metadata
> > > storage. It is simply just too technical. That does not mean that we
> > > cannot use that stuff under the hood though.
> > >
> > > > Timestamps are handled via named graphs , also known as context
> > > > (RDF quadruples).
> > >
> > > Are you suggesting putting the mtime in the name of each RDF triple?
> > > If we are to support timestamps I don't think we should expose them as
> > > RDF quadruples because I still think that it is too much abstraction
> > > to present to the end user developer.
> > No, named graphs mean that each triple becomes a quadruple and the forth
> > node is used to group triples together into subgraphs. These subgraphs
> > are then annotated with arbitrary information such as creation date.
> it (quad-store) sounds quite bloated
> would it not be better to have a single metadata_changed_timestamp
> attribute on the entity itself rather than on each and every triple/quad
> metadata item?
This approach would probably work well for file metadata. However if we add
system settings to the mix it becomes much harder because each settings
triple needs a timestamp.
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