Matt, it's great to hear that you're planning on getting SemLayers up to
date with SMW - I'm definitely thinking about more map-based querying for my
TechPresentations.org and want to start collecting full venue addresses for
events to enable better map views.
Also, I wonder if you're going to extend Semantic Forms with data entry tool
as well.
Sergey
On Sun, Mar 16, 2008 at 2:22 PM, Matt Williamson <[EMAIL PROTECTED]>
wrote:
> Markus,
>
> Thanks!
>
> > * If you need to exectute an #ask query internally, then you first
> > need to
> > forge a query object (SMWQuery), which consists of some SMWDescription
> > together with some additional parameters. This can be created
> > directly by
> > building SMWDescription objects as required, or from #ask query syntax
> > (slower) by parsing it with SMWQueryProcessor::createQuery(). Once
> > you have a
> > query object, you can execute this query and retrieve the result. To
> > get the
> > result object (similar to the one the printer gets), use
> > smwfGetStore()->getQueryResult($query). To format such a result with
> > an
> > existing printer, you can again call some printer's getResult()
> > method.
>
>
> This sounds perfect! The SMWStore->getQueryResult() part was the bit I
> was missing, I think--plus exactly how to create the SMWQuery. Good to
> know there's a fast vs.slow way to do it, too. The result object is
> exactly what I need, I just hadn't figured out how to get one outside
> the context of a ResultPrinter.
>
> > * If you need just selected information, there are simpler (and much
> > faster)
> > ways than issuing an #ask query. Basically, these are the various
> > get...
> > functions in SMWStore (includes/store/SMW_Store.php). You can call
> > those
> > methods on the object returned by smwfGetStore() in any context.
>
>
> Yes, I noticed the methods like getPropertyValues and
> getPropertySubjects and those will definitely be useful in several
> cases. Question: in that object's code comments, is a "subject" the
> same thing as a page or sub-page? It looks like it, but I'm not 100%
> sure. If not, what are the differences (or do I have it wrong entirely)?
>
> > Since very recently, SMW in SVN also has a method
> > SMWStore::getSemanticData()
> > that will retrieve the whole "Factbox" for one page from the store
> > in one
> > call. If you need to access many properties, this is likely to be
> > faster than
> > having individual calls for each. For further speed-up, this method
> > also
> > allows you to supply a simple "filter" array, that instructs the
> > store to
> > retrieve only certain special properties or only properties of certain
> > datatypes.
>
>
> Really? That's excellent...any idea when this will make it into the
> stable release? That would certainly speed up at least a few cases.
> But I'm figuring I'd better target a stable release for now. This
> would be perfect for retrieving the properties of a Layer in my
> extension (marker icon, offset parameters, dimensions, etc.). Anyway,
> I should be able to accomplish this without it, but I'll definitely
> keep that in mind for future optimization.
>
> Thanks again!
>
> -Matt
>
>
>
> On Mar 16, 2008, at 1:52 PM, Markus Krötzsch wrote:
>
> > On Samstag, 15. März 2008, Matt Williamson wrote:
> >> Markus,
> >>
> >> Greetings from the presumed-dead author of Semantic Layers. I'm
> >> finally starting to update SL for compatibility with SMW 1.0--and
> >> having some luck so far, I've made good progress on a subclass of
> >> SMWResultPrinter that lets you specify "map" as the format, and that
> >> part seems to be progressing well.
> >
> > Very nice, the extension surely has great potential in many
> > applications.
> >
> >>
> >> However, for several of the other features I need to do exactly what
> >> you mention below--use the existing SMW objects to submit and process
> >> an arbitrary query, and get the results back in a form I can
> >> manipulate programmatically. Glad to hear that accessing the database
> >> is discouraged, as I was loathe to do so.
> >>
> >> But I'm having a bit of trouble figuring it out, since the pipeline
> >> seems primarily geared towards producing printed output. So, could
> >> you
> >> elaborate a bit on precisely how one might use SMW_Store within an
> >> extension, to process and retrieve a query result, which will be used
> >> for something other than printing out the results?
> >
> > If you have written am SMW query printer, then you already should
> > get a
> > result-object in there. I hope that this kind of object is OK for
> > your needs,
> > since there is no other query result container at the moment. If you
> > want to
> > get further information (while printing the result?), then there are
> > several
> > options:
> >
> > * If you need to exectute an #ask query internally, then you first
> > need to
> > forge a query object (SMWQuery), which consists of some SMWDescription
> > together with some additional parameters. This can be created
> > directly by
> > building SMWDescription objects as required, or from #ask query syntax
> > (slower) by parsing it with SMWQueryProcessor::createQuery(). Once
> > you have a
> > query object, you can execute this query and retrieve the result. To
> > get the
> > result object (similar to the one the printer gets), use
> > smwfGetStore()->getQueryResult($query). To format such a result with
> > an
> > existing printer, you can again call some printer's getResult()
> > method.
> >
> > Some combination of those steps (especially combining query
> > execution and
> > formatting) are implemented in methods of SMWQueryPorcessor, see e.g.
> > getResultFromQuery(). Even if those methods are not useful for you,
> > they
> > might give you the idea how to proceed step by step.
> >
> > * If you need just selected information, there are simpler (and much
> > faster)
> > ways than issuing an #ask query. Basically, these are the various
> > get...
> > functions in SMWStore (includes/store/SMW_Store.php). You can call
> > those
> > methods on the object returned by smwfGetStore() in any context.
> >
> > Since very recently, SMW in SVN also has a method
> > SMWStore::getSemanticData()
> > that will retrieve the whole "Factbox" for one page from the store
> > in one
> > call. If you need to access many properties, this is likely to be
> > faster than
> > having individual calls for each. For further speed-up, this method
> > also
> > allows you to supply a simple "filter" array, that instructs the
> > store to
> > retrieve only certain special properties or only properties of certain
> > datatypes.
> >
> >
> > If this is not what you thought of, some more details on your plans
> > would be
> > useful.
> >
> > Regards,
> >
> > Markus
> >
> >>
> >> Thanks!
> >>
> >> -Matt
> >>
> >> P.S.: The improvements in 1.0 over 0.7 are terrific so far for
> >> extension developers--as I said, making my own ResultPrinter was
> >> practically a piece of cake. Thanks again!
> >
> > Great that this works for you. Since result printers do really not
> > increase
> > the weight of the software, we are usually happy to add contributed
> > printers
> > to the main distribution (printer registration in extensions, also
> > when
> > compared to the mechanism for extension datatypes, is still somewhat
> > under-developed).
> >
> >>
> >> On Feb 9, 2008, at 7:40 AM, Markus Krötzsch wrote:
> >>> On Freitag, 8. Februar 2008, Jeff Thompson wrote:
> >>>> Is there a document (or an email message or comments in the code)
> >>>> that
> >>>> describes the database schema that SMW uses to store semantic data,
> >>>> including the change history? I could read the code to try to
> >>>> figure it
> >>>> out, but I wondered if it is already explained somewhere.
> >>>
> >>> AFAIR it is not. We might add such a resource *but* we strongly
> >>> discourage any
> >>> direct access to SMW DB tables by extensions anyway. The reason is
> >>> that SMW
> >>> was designed to allow complete replacement of the semantic storage
> >>> implementation with bascially no changes in the SMW code. We might
> >>> make us of
> >>> that option.
> >>>
> >>> If you want to access semantic data programmatically, consider the
> >>> storage
> >>> interface methods (SMW_Store.php) if in PHP, and the RDF export
> >>> (Special:ExportRDF or full dump via SMW_dumpRDF.php) if you are
> >>> outside PHP.
> >>> If you need something in between, then subclassing the current MySQL
> >>> storage
> >>> implementation might be a good idea.
> >>>
> >>> Cheers,
> >>>
> >>> Markus
> >>>
> >>>> Thanks,
> >>>> - Jeff
> >>>>
> >>>>
> >>>>
> >>>>
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> >>>
> >>> --
> >>> Markus Krötzsch
> >>> Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
> >>> phone +49 (0)721 608 7362 fax +49 (0)721 608 5998
> >>> [EMAIL PROTECTED] www http://korrekt.org
> >>>
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> >
> >
> >
> > --
> > Markus Krötzsch
> > Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
> > phone +49 (0)721 608 7362 fax +49 (0)721 608 5998
> > [EMAIL PROTECTED] www http://korrekt.org
>
>
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--
Sergey Chernyshev
http://www.sergeychernyshev.com/
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