semantic web - Why some rdf files does not contain <rdf:Description rdf:about=...>? -

-

i'm using jena write rdf file describes online posts. according sioc ontology/namespace i'm using there is, instance, following:

  • class: sioc:post
  • property: sioc:has_creator

how can i, in jena, include sioc:post in file 

<sioc:post rdf:about="http://example.com/vb/1035092">

instead of 

<rdf:description rdf:about="http://example.com/vb/1035092">

and best practice?

both of answers far make points:

  • you should not pay attention particular serialization of rdf graph, because there lots of different serializations, , should accessing them using api exposes graph, not serialization. (see, instance, don't query rdf (or owl) xpath in 1 of previous answers, comments depending on particular xml serialization.)
  • the difference you're seeing simple rdf/xml serialization use lots of rdf:description elements, , these contain rdf:type elements indicate types of described element. however, rdf/xml serialization format defines many abbreviations can used make serialization of graph shorter, more readable, and, in cases, more traditional xml document. others have mentioned using type element name 1 such abbreviation, think it's worth examining spec on point. particular abbreviation defined in 2.13 typed nodes:

it common rdf graphs have rdf:type predicates subject nodes. these conventionally called typed nodes in graph, or typed node elements in rdf/xml. rdf/xml allows triple expressed more concisely. replacing rdf:description node element name namespaced-element corresponding rdf uri reference of value of type relationship. there may, of course, multiple rdf:type predicates 1 can used in way, others must remain property elements or property attributes.

the typed node elements commonly used in rdf/xml built-in classes in rdf vocabulary: rdf:seq, rdf:bag, rdf:alt, rdf:statement, rdf:property , rdf:list.

for example, rdf/xml in example 14 written shown in example 15.

example 14: complete example rdf:type (example14.rdf output example14.nt)

<?xml version="1.0"?> <rdf:rdf xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"          xmlns:dc="http://purl.org/dc/elements/1.1/"          xmlns:ex="http://example.org/stuff/1.0/">   <rdf:description rdf:about="http://example.org/thing">     <rdf:type rdf:resource="http://example.org/stuff/1.0/document"/>     <dc:title>a marvelous thing</dc:title>   </rdf:description> </rdf:rdf>

example 15: complete example using typed node element replace rdf:type (example15.rdf output example15.nt)

<?xml version="1.0"?> <rdf:rdf xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"          xmlns:dc="http://purl.org/dc/elements/1.1/"          xmlns:ex="http://example.org/stuff/1.0/">   <ex:document rdf:about="http://example.org/thing">     <dc:title>a marvelous thing</dc:title>   </ex:document> </rdf:rdf>

if you're using jena, can extensive control on way rdf/xml output formatted. these options documented in advanced rdf/xml output section of documentation. however, case want, serializing in rdf/xml versus rdf/xml-abbrev take care of want do. instance, @ results using jena command line rdfcat tool. here's our data (in turtle):

# actual namespace doesn't matter example. @prefix sioc: <http://example.org/> .   <http://example.com/vb/1035092>   sioc:post ;   sioc:has_creator "someone" .

let's convert simple rdf/xml:

$ rdfcat -out rdf/xml data.n3 <rdf:rdf     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"     xmlns:sioc="http://example.org/" >    <rdf:description rdf:about="http://example.com/vb/1035092">     <rdf:type rdf:resource="http://example.org/post"/>     <sioc:has_creator>someone</sioc:has_creator>   </rdf:description> </rdf:rdf>

now let's convert rdf/xml-abbrev:

$ rdfcat -out rdf/xml-abbrev data.n3 <rdf:rdf     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"     xmlns:sioc="http://example.org/">   <sioc:post rdf:about="http://example.com/vb/1035092">     <sioc:has_creator>someone</sioc:has_creator>   </sioc:post> </rdf:rdf>

in first case see rdf:description element rdf:type , sioc:has_creator subelements, in second case see sioc:post element sioc:has_creator subelement.

as best practice, don't know matters. rdf/xml-abbrev typically bit shorter, incur less network overhead on transmission, storage on disk, , easier read. simpler rdf/xml faster write, though. on graphs won't make big difference, generating rdf/xml-abbrev can pretty expensive, a recent thread on jena mailing list discusses.


Comments

Post a Comment

Popular posts from this blog

ios - UICollectionView Self Sizing Cells with Auto Layout -

-
Image
i'm trying self sizing uicollectionviewcells working auto layout, can't seem cells size content. i'm having trouble understanding how cell's size updated contents of what's inside cell's contentview. here's setup i've tried: custom uicollectionviewcell uitextview in contentview. scrolling uitextview disabled. the contentview's horizontal constraint is: "h:|[_textview(320)]", i.e. uitextview pinned left of cell explicit width of 320. the contentview's vertical constraint is: "v:|-0-[_textview]", i.e. uitextview pinned top of cell. the uitextview has height constraint set constant uitextview reports fit text. here's looks cell background set red, , uitextview background set blue: i put project i've been playing on github here . updated ios 9 after seeing github solution break under ios 9 got time investigate issue fully. have updated repo include several examples of different configurations s...
Read more

DOM Manipulation in Wordpress (and elsewhere) using php -

-
DOM Manipulation in Wordpress (and elsewhere) using php - i'm quite new dom manipulation world , head start in order avoid mutual errors. i looking efficient way manipulate content generated wordpress using php. @ moment using simple html dom seems work fine. found domdocument , few others , helpfull if cleared out 1 faster, improve or @ to the lowest degree generate less errors in case of bad markup. also on side can explain syntax (instead of $html @$html) thank much php wordpress domdocument simple-html-dom
Read more

asp.net - Passing parameter to telerik popup -

-
is there way pass parameter telerik similar window.showmodaldialog the way call window.showmodaldialog : window.showmodaldialog(pagename, myargs, 'status:no;dialoghide=true;help:no') myargs parameter passing popup try likes , <script type="text/javascript"> function openradwin(myargs) { radopen("yourpagename.aspx?parameter=" + myargs , "radwindow1"); } </script> <telerik:radwindowmanager id="radwindowmanager1" runat="server" enableshadow="true" visiblestatusbar="false"> <windows> <telerik:radwindow id="radwindow1" runat="server" showcontentduringload="false" width="400px" height="400px" title="telerik radwindow" behaviors="default"> </telerik:radwindow> </windows> </telerik:radwindowmanager> and , @ page_load of...
Read more