--- a/rdf-primer/index.html Sun Dec 15 22:59:35 2013 +0100
+++ b/rdf-primer/index.html Sun Dec 15 23:04:49 2013 +0100
@@ -12,7 +12,7 @@
// specification status (e.g. WD, LC, WG-NOTE, etc.). If in doubt use ED.
specStatus: "FPWD",
- noRecTrack: true,
+ // noRecTrack: true,
// the specification's short name, as in http://www.w3.org/TR/short-name/
shortName: "rdf11-primer",
@@ -22,7 +22,7 @@
// subtitle : "an excellent document",
// if you wish the publication date to be other than today, set this
- // publishDate: "2013-11-05",
+ publishDate: "2013-12-17",
// if the specification's copyright date is a range of years, specify
@@ -114,35 +114,22 @@
<body>
-<div class="head">
<section id="abstract">
-
<p>The Resource Description Framework (RDF) is a language for
representing information about resources in the World Wide
Web. This primer is designed to provide the reader with the basic
knowledge required to effectively use RDF. It introduces the basic
concepts of RDF and shows concrete examples of the use of RDF. </p>
-</section>
-
-<section id="sotd">
-
- <p>The RDF Working Group expects this document to become a Working
- Group Note. </p>
-
-</section>
-
+ </section>
+ <section id="sotd">
+ <p>The RDF Working Group expects this document to become a Working
+ Group Note.</p>
+ </section>
</div>
<section id="section-Introduction">
<h2>Introduction</h2>
- <div class="issue">This document reflects current progress of the RDF Working
- Group towards updating the
- <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">2004
- version of the <em>RDF Primer</em></a>. The
- editors expect to work on a number of issues, some of which are
- listed in boxes like this throughout the document.</div>
-
<p class="note">This primer is an informative document. The
purpose is to give a light-weight overview of RDF 1.1.
Secs. 3-5 can be used as a minimalist introduction into the key
@@ -175,8 +162,8 @@
qualified as Linked Data [[LINKED-DATA]]. </p>
<div class="note">
- An IRI is an "International Resource Identifier". See Sec. <a
- href="#subsection-IRI">"IRI"</a> for details.
+ An IRI is an "International Resource Identifier". See <a
+ href="#subsection-IRI">Sec. 3.2</a> for details.
</div>
<p>This document is not normative and does not give a complete
@@ -193,16 +180,14 @@
<li>Turtle [[!TURTLE]] and TriG [[!TRIG]]</li>
<li>JSON-LD [[!JSON-LD]] (JSON based)</li>
<li>RDFa [[!RDFA-PRIMER]] (for HTML embedding)</li>
- <li>N-Triples and N-Quads (line-based exchange formats)</li>
+ <li>N-Triples [[!N-TRIPLES]] and N-Quads [[N-QUADS]]
+ (line-based exchange formats)</li>
+ <li>RDF/XML [[!RDF11-XML]] (the original 2004 syntax, updated
+ for RDF 1.1)</li>
</ul></li>
- <li>A document describing RDF Schema [[!RDF-SCHEMA]], which
+ <li>A document describing RDF Schema [[RDF11-SCHEMA]], which
provides a data-modeling vocabulary for RDF data. </li>
</ul>
-
- <!--
- <p>This primer provides a roadmap for people who want to study these
- normative RDF documents (see Sec. <a href="#section-roadmap">"Roadmap"</a>). </p>
- -->
</section>
@@ -295,9 +280,10 @@
<strong>graph</strong>. Graphs consists
of nodes and arcs. The subjects and
objects of the triples make up the nodes in the graph; the
- predicates form the arcs. </p>
+ predicates form the arcs. <a href="#fig-example-graph">Fig. 1</a>
+ shows the graph resulting from the sample triples.</p>
- <figure>
+ <figure id="fig-example-graph">
<img class="graph" src="example-graph.jpg"
alt="Informal graphs of the sample triples">
<figcaption>Informal graph of the sample triples</figcaption>
@@ -312,9 +298,8 @@
particular encoding. Different encodings may
produce exactly the same graph from the perspective of the
abstract syntax. The semantics of RDF graphs [[RDF11-MT]] are defined in
- terms of this abstract syntax. RDF syntax is introduced
- later in Sec. <a href="#section-graph-syntax">Writing RDF
- graphs</a>.</p>
+ terms of this abstract syntax. Concrete RDF syntax is introduced
+ later in <a href="#section-graph-syntax">Sec. 5</a>.</p>
<p>In the next three subsections we discuss the three types of RDF data
that occur in triples: IRIs, literals and blank nodes. </p>
@@ -356,8 +341,8 @@
href="http://wiki.dbpedia.org/Datasets#h338-3">DBpedia</a> uses IRIs of the form
<code>http://dbpedia.org/resource/Name</code> to denote the thing
described by the corresponding Wikipedia article.
- RDF vocabularies are discussed in more detail in Sec.
- <a href="#section-vocabulary">"RDF vocabularies"</a>. </p>
+ RDF vocabularies are discussed in more detail in
+ <a href="#section-vocabulary">Sec. 4</a>. </p>
</section>
@@ -365,7 +350,8 @@
<h3>Literals</h3>
- <p><a href="http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal">Literals</a>
+ <p>
+ <a href="http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal">Literals</a>
are basic values that are not IRIs. Examples of literals include
strings such as "La Joconde", dates such as "the 4th of July, 1990"
and numbers such as "3.14159".
@@ -418,13 +404,6 @@
to denote resources without explicitly naming them with an
IRI.</p>
- <!--
- <p class="note">Blank nodes can make RDF look complicated,
- especially when one consults details about blank nodes in the RDF Concepts
- [[RDF11-CONCEPTS]] and RDF Semantics [[RDF11-MT]] documents. It
- should be noted that many RDF users in practice don't use blank nodes. </p>
- -->
-
</section>
<section id="subsection-multiple-graphs">
@@ -432,10 +411,15 @@
<h3>Multiple graphs</h3>
<p>RDF provides a mechanism to group RDF statements in multiple
- graphs and associate each graph with an IRI.<p>
+ graphs and associate each graph with an IRI. Multiple graphs in
+ an RDF document constitute an
+ <a href="http://www.w3.org/TR/rdf11-concepts/#section-dataset">RDF
+ dataset</a>. An RDF dataset may have multiple named graphs and
+ at most one default graph (i.e. a graph without a name). </p><p>
<p>For example, the
- statements in the <a href="#subsection-triple">first example</a> could be grouped in two
+ statements in the <a href="#subsection-triple">first example</a>
+ could be grouped in two named
graphs. A first graph could be provided by a social networking
site and identified by <code>http://example.org/bob</code>:</p>
@@ -461,35 +445,31 @@
<The video 'La Joconde à Washington'> <is about> <the Mona Lisa>
</pre>
- <p>We can then write down triples that include a graph name,
- for example:</p>
+ <p>In the example default (unnamed) graph below we see two triples that
+ have a graph name as subject: </p>
<pre>
<http://example.org/bob> <is published by> <http://example.org>.
<http://example.org/bob> <has license> <http://creativecommons.org/licenses/by/3.0/>.
</pre>
- <p>These two triples could be interpreted as license and
- provenance information of the graph
- <code>http://example.org/bob</code>.</p>
-
- <p class="note">RDF does not define the way in which the graph name
- and the graph are related. It is therefore up to application developers to
- decide how to interpret such triples.</p>
+ <p>RDF 1.1 doesn't prescribe any specific semantics for
+ datasets. Possible semantics are described in a separate note
+ [[RDF11-DATASETS]]. In this example dataset we assume graph
+ names represent the source of the RDF data held within the
+ corresponding graphs, i.e. by retrieving
+ <code><http://example.org/bob></code> we would get access to the four triples
+ in that graph. In the example default graph we associate provenance
+ information (publisher, license) with the
+ <code><http://example.org/bob></code> graph.</p>
- <p class="issue">The text above is still being debated and may
- be adapted/removed in future versions.
- </p>
+ <p class="note">RDF provides no way to convey this semantic
+ assumption (i.e., that graph names represent the source of the
+ RDF data) to other readers of the dataset. Those readers will
+ need to rely on out-of-band knowledge to interpret the dataset
+ in the intended way. </p>
- <p>Multiple graphs in an RDF document constitute an <a
- href="http://www.w3.org/TR/rdf11-concepts/#section-dataset">RDF
- dataset</a>. An RDF dataset may have multiple named graphs and
- one default graph (i.e. without a name). The default graph
- could, for example, be used to record graph metadata, such as
- the two last statements which constitute publisher and license
- metadata about the first graph.</p>
-
- <p>Sec. <a href="#subsection-trig">"Trig"</a> provides an example
+ <p><a href="#subsection-trig">Sec. 5.2</a> provides an example
of concrete syntax for this example.</p>
<p class="note">Multiple graphs are a recent extension of the RDF
@@ -516,7 +496,7 @@
<p>To support the definition of vocabularies RDF provides
the RDF-Schema language
- [[!RDF-SCHEMA]]. This language allows one to define semantic
+ [[!RDF11-SCHEMA]]. This language allows one to define semantic
characteristics of
RDF data. For example, one can state that the IRI
<code>ex:friendOf</code> can be used as a property and that the
@@ -581,8 +561,8 @@
</table>
<p class="note">The syntactic form (second column) is in a prefix
-notation wich is discussed in more detail in Sec.
-<a href="#section-graph-syntax">"Writing RDF Graphs"</a>.
+notation wich is discussed in more detail in
+<a href="#section-graph-syntax">Sec. 5</a>.
The fact that the constructs have two different prefixes
(<code>rdf:</code> and <code>rdfs:</code>) is a somewhat annoying
historical artefact, which is preserved for backward
@@ -605,8 +585,8 @@
vocabularies are:</p>
<dl>
- <dt><a href="http://dublincore.org/documents/dcmi-terms/">Dublic Core</a></dt>
- <dd>The Dublic Core Metadata Initiative maintains a metadata element
+ <dt><a href="http://dublincore.org/documents/dcmi-terms/">Dublin Core</a></dt>
+ <dd>The Dublin Core Metadata Initiative maintains a metadata element
set for describing a wide range of resources. The vocabulary provides
properties such as "creator", "publisher" and "title".</dd>
@@ -656,8 +636,8 @@
consumption. The final subsection lists the other RDF syntaxes,
which include RDFa (for HTML embedding), JSON-LD (JSON-based syntax),
N-Triples/N-Quads (line-based exchange formats) and RDF/XML. In
- Appendix <a href="#section-other-syntaxes">"RDF syntax
- examples"</a> the reader can find for each RDF syntax
+ Appendix <a href="#section-other-syntaxes">Appendix C</a> the
+ reader can find for each RDF syntax
corresponding examples of the ones in this section. </p>
<section id="subsection-turtle">
@@ -771,7 +751,7 @@
</pre>
<p>The term <code>_:x</code> is a blank node. It represents some
-unamed tree depicted in the Mona Lisa painting and belonging to the
+unnamed tree depicted in the Mona Lisa painting and belonging to the
"Cypress" class. </p>
<p>The above is by no means a full account of the Turtle syntax. For
@@ -948,14 +928,7 @@
an example of an RDF Schema entailment. For detailed
information about entailment regimes
please consult the RDF Semantics document [[RDF11-MT]]. </p>
-
- <!--
- <p class="note">As we saw in the earlier <a
- href="#section-rurtle-example">Turtle example</a> (line 9) we could have
- used the shorthand <code>ex:bob a foaf:Person</code> for the example
- above. </p>
- -->
-
+
<p>The semantics of RDF also tell us that the triple:</p>
<pre>
<code>ex:bob ex:age "forty"^^xsd:integer . </code>
@@ -969,7 +942,7 @@
and language-tagged literals.</p>
<p>Unlike many other data
- modeling languages, RDF Schema allows considerble modelling
+ modeling languages, RDF Schema allows considerable modeling
freedom. For example, the same entity may be used
as both a class and a property. Also, there is no strict separation
between the world of "classes" and of "instances". Therefore, RDF
@@ -1045,9 +1018,6 @@
the references to get more detailed information. You might also
want to take a look at the <a
href="http://www.w3.org/standards/semanticweb/data">W3C Linked Data page</a>. </p>
-
- <p class="issue">TODO: check whther this is the right place to
- point to in W3C space.</p>
</section>
@@ -1058,32 +1028,17 @@
different syntactic forms. Pierre-Antoine Champin provided the
alternate JSON-LD example. Andrew Wood designed the graph
diagrams. We are grateful for the comments provided by (in
- alphabetical order) Dan Brickley, Pierre-Antoine Champin, Pat
- Hayes and David Wood. </p>
-
- <p class="issue">Should we still inclue the 2004 acknowledgements,
- given that the document is completely rewritten?</p>
- <!--
- <p>The RDF 2004 editors acknowledge the contributions from many
- members of the RDF Core Working Group. Specific thanks are due to
- Art Barstow, Dave Beckett, Dan Brickley, Ron Daniel, Ben
- Hammersley, Martyn Horner, Graham Klyne, Sean Palmer, Patrick
- Stickler, Aaron Swartz, Ralph Swick, and Garret Wilson who,
- together with the many people who commented on earlier versions of
- the Primer, provided valuable contributions to this document.
- In addition, this document contains a significant contribution from
- Pat Hayes, Sergey Melnik, and Patrick Stickler, who led the
- development of the RDF datatype facilities described in the RDF
- family of specifications. </p>
- -->
-
+ alphabetical order) Thomas Baker, Dan Brickley, Pierre-Antoine
+ Champin, Sandro Hawke, Patrick
+ Hayes, Ivan Herman, Markus Lanthaler, and David Wood. </p>
+
</section>
<section class="appendix" id="changes">
<h2>Changes</h2>
<dl>
- <dt>Changes compared to 2004 version</dt>
+ <dt>Changes compared to 2004 Primer [[RDF-PRIMER]]</dt>
<dd>The introduction contains a number of sentences from the
2004 document. For the rest the RDF 1.1 Primer is a completely
new document.</dd>
@@ -1094,7 +1049,7 @@
<h2>Examples of RDF syntaxes</h2>
-<p>In Sec. <a href="#section-graph-syntax">"Writing RDF Graphs"</a> the
+<p>In <a href="#section-graph-syntax">Sec. 5</a> the
different concrete syntaxes of RDF are briefly described. Examples are
given only of the Turtle and TriG syntax. This appendix lists
corresponding examples for the other syntaxes listed. The
@@ -1137,7 +1092,12 @@
<section id="subsection-jsonld">
- <h3>JSON-LD</h3>
+ <p class="issue">
+ We should consider annotating the JSON-LD examples in this
+ subsection, thus making it a mini JSON-LD primer, and/or including
+ one of the JSON-LD example in Sec. 5. </p>
+
+ <h3>JSON-LD</h3>
Single-graph example: