--- a/rdf-primer/index.html Wed Feb 19 13:56:36 2014 +0100
+++ b/rdf-primer/index.html Wed Feb 19 15:00:48 2014 +0100
@@ -118,7 +118,11 @@
<section id="abstract">
<p>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>
+ concepts of RDF and shows concrete examples of the use of RDF.
+ Secs. 3-5 can be used as a minimalist introduction into the key
+ elements of RDF. Changes between RDF 1.1
+ and RDF 1.0 (2004 version) are summarized in a separate document: "What's New in RDF
+ 1.1" [[RDF11-NEW]].</p>
</section>
<section id="sotd">
<p>This document is part of the RDF 1.1 document suite. It is an
@@ -130,15 +134,9 @@
<section id="section-Introduction">
<h2>Introduction</h2>
-
- <p class="note">This document gives a light-weight overview of RDF 1.1.
- Secs. 3-5 can be used as a minimalist introduction into the key
- elements of RDF. Changes between RDF 1.1
- and RDF 1.0 (2004 version) are summarized in a separate document: "What's New in RDF
- 1.1" [[RDF11-NEW]].</p>
<p>The Resource Description Framework (RDF) is a framework for
- expressing information about <strong>resources</strong>. Resources
+ expressing information about <strong id="resource">resources</strong>. Resources
can be anything, including documents, people, physical objects, and abstract
concepts.</p>
@@ -170,17 +168,17 @@
<ul>
<li>A document describing the basic concepts underlying RDF, as
well as abstract syntax ("RDF Concepts and Abstract Syntax")
- [[!RDF11-CONCEPTS]]</li>
+ [[RDF11-CONCEPTS]]</li>
<li>A document describing the formal model-theoretic semantics
- of RDF ("RDF Semantics") [[!RDF11-MT]]</li>
+ of RDF ("RDF Semantics") [[RDF11-MT]]</li>
<li>Specifications of concrete syntaxes for RDF:
<ul>
- <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 [[!N-TRIPLES]] and N-Quads [[!N-QUADS]]
+ <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 [[N-TRIPLES]] and N-Quads [[N-QUADS]]
(line-based exchange formats)</li>
- <li>RDF/XML [[!RDF11-XML]] (the original 2004 syntax, updated
+ <li>RDF/XML [[RDF11-XML]] (the original 2004 syntax, updated
for RDF 1.1)</li>
</ul></li>
<li>A document describing RDF Schema [[RDF11-SCHEMA]], which
@@ -190,7 +188,7 @@
</section>
<section id="section-use-cases">
- <h2>Why use RDF?</h2>
+ <h2>Why Use RDF?</h2>
<p>The following illustrates various different uses of RDF, aimed
at different communities of practice.</p>
@@ -219,7 +217,7 @@
between databases.</li>
<li>Interlinking various datasets within an organisation,
enabling cross-dataset queries to
- be performed using SPARQL [[!SPARQL11-OVERVIEW]].</li>
+ be performed using SPARQL [[SPARQL11-OVERVIEW]].</li>
</ul>
</section>
@@ -324,7 +322,7 @@
or how to access it. The notion of IRI is a
generalization of URI (Uniform Resource Identifier), allowing
non-ASCII characters to be used in the IRI character string. IRIs are specified
- in RFC 3987 [[!RFC3987]].
+ in RFC 3987 [[RFC3987]].
<p>IRIs can appear in <strong>all three positions</strong> of a triple. </p>
@@ -461,7 +459,7 @@
</pre>
<p>The IRI associated with the graph is
- called the "graph name" [[!RDF11-CONCEPTS]]. </p>
+ called the "graph name" [[RDF11-CONCEPTS]]. </p>
<p>A second graph could be provided by <a
href="http://www.wikidata.org/">Wikidata</a>
@@ -522,7 +520,7 @@
<p>To support the definition of vocabularies RDF provides
the RDF-Schema language
- [[!RDF11-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>http://www.example.org/friendOf</code> can be used as a property and that the
@@ -666,17 +664,19 @@
graphs. However, different ways of writing down the same graph lead
to exactly the same triples, and are thus logically equivalent. </p>
- <p>In this section we introduce the Turtle family of RDF languages
+ <p>In this section we briefly introduce, through an annotated example, the following syntaxes:
+<ul>
+ <li>Turtle family of RDF languages
(<a href="#section-n-triples">N-Triples</a>,
<a href="#section-turtle">Turtle</a>,
<a href="#section-trig">TriG</a> and
- <a href="#section-n-quads">N-Quads</a>)
- and the JSON-based RDF syntax <a href="#section-json-ld">JSON-LD</a>.
- Two other RDF syntaxes,
- <a href="#appendix-rdfa">RDFa</a> (for HTML and XML embedding)
- and <a href="#appendix-rdfxml">RDF/XML</a>, are briefly described later on. </p>
+ <a href="#section-n-quads">N-Quads</a>);</li>
+ <li><a href="#section-json-ld">JSON-LD</a> (JSON-based);</li>
+ <li><a href="#section-rdfa">RDFa</a> (for HTML and XML embedding);</li>
+ <li><a href="#section-rdfxml">RDF/XML</a> (XML syntax for RDF). </p>
+</ul>
-<section>
+<section id="section-turtle-family">
<h3>Turtle family of RDF languages</h3>
<p>In this subsection we introduce four concrete syntaxes for RDF
@@ -930,9 +930,7 @@
<p><p>Like N-Triples, N-Quads is typically used for exchanging large RDF datasets and for
processing RDF with line-oriented text processing tools. </p>
-
-<p class="issue">Include a Note that N-Quads is *not* a subset of TriG?</p>
-
+
</section>
</section>
@@ -992,43 +990,160 @@
</section>
- <section id="section-other-syntaxes">
-
- <h3>Other concrete syntaxes for RDF</h3>
-
- <p>Next to the Turtle family of languages and JSON-LD there are two other concrete syntaxes
- for RDF data: RDFa and RDF/XML. These syntaxes were developed to cater to specific
- application and/or usage needs: </p>
+<section id="section-rdfa">
+<h3>RDFa</h3>
+
+<p>RDFa [[RDFA-PRIMER]] is an RDF syntax that can be used to embed RDF data within
+HTML and XML documents. This enables, for example, search engines to aggregate
+this data when crawling the Web and use it to enrich search
+results (see, e.g., <a href="http://schema.org">schema.org</a>
+and <a href="https://support.google.com/webmasters/answer/99170?hl=en">Rich
+Snippets</a>). </p>
- <dl>
- <dt>RDFa</dt>
- <dd>RDFa [[RDFA-PRIMER]]
- can be used to embed RDF data within
- HTML documents. This enables, for example, search engines to aggregate
- this data when crawling the Web and use it to enrich search
- results (see, e.g.,
- <a href="http://schema.org">schema.org</a>
- and <a
- href="https://support.google.com/webmasters/answer/99170?hl=en">Rich
- Snippets</a>). <a href="#appendix-rdfa">Appendix C.1</a>
- provides an annotated RDFa example.
- </dd>
+<p>The HTML example below encodes the
+RDF graph depicted in <a href="#fig4">Fig. 4</a>:</p>
+
+<pre class="example" id="rdfa-example">
+01 <body prefix="foaf: http://xmlns.com/foaf/0.1/
+02 schema: http://schema.org/
+03 dcterms: http://purl.org/dc/terms/">
+04 <div resource="http://example.org/bob#me" typeof="foaf:Person">
+05 <p>
+06 Bob knows <a property="foaf:knows" href="http://example.org/alice#me">Alice</a>
+07 and was born on the <time property="schema:birthDate">1990-07-04</time>.
+08 </p>
+09 <p>
+10 Bob is interested in <span property="foaf:topic_interest"
+11 resource="http://www.wikidata.org/entity/">the Mona Lisa</span>.
+12 </p>
+13 </div>
+14 <div resource="http://www.wikidata.org/entity/">
+15 <p>
+16 The <span property="dcterms:title">Mona Lisa</span> was painted by
+17 <a property="dcterms:creator" href="http://dbpedia.org/resource/Leonardo_da_Vinci">Leonardo da Vinci</a>
+18 and is the subject of the video
+19 <a href="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">'La Joconde à Washington'</a>.
+20 </p>
+21 </div>
+22 <div resource="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">
+23 <link property="dcterms:subject" href="http://www.wikidata.org/entity/Q12418">
+24 </div>
+25 </body>
+</pre>
- <dt>RDF/XML</dt>
- <dd>RDF/XML [[RDF-SYNTAX-GRAMMAR]]
- provides an XML syntax for RDF
- graphs. When RDF was original developed in the late 1990s, this was its
- only syntax, and some people still call this syntax "RDF". In 2001, a
- precursor to Turtle called "N3" was proposed, and gradually the other
- syntaxes listed here have been adopted and standardizedR.
- <a href="#appendix-rdfxml">Appendix C.2</a>
- provides an annotated RDF/XML example.
- </dd>
- </dl>
+<p class="issue">Textual description of example in progress (does not
+reflect yet the new RDFa Lite format of the example)</p>
- <p>For more information about these syntaxes consult the references.</p>
+<p>RDFa introduces a number of special attributes that enable the
+specification of triples within HTML. For example, the <code>div</code> elements
+in lines 4 and 14 have a <code>resource</code>
+attribute, specifying the IRI about which RDF statements can be made within this
+block. In line 6 we see a <code>property</code> attribute; the value
+of this attribute is interpreted as an RDF property IRI. The property
+is specified as an attribute of an <code>a</code> element; the
+<code>href</code> attribute value is interpreted here as the object of the
+triple. This results in the triple: <p>
- </section>
+<pre class="example">
+<http://example.org/bob#me> <http://xmlns.com/foaf/0.1/knows> <http://example.org/alice#me> .
+</pre>
+
+<p>In line 7 we see a triple with as object a literal value. The
+<code>property</code> attribute is specified here on the HTML
+<code>time</code> element. HTML requires that the content of the time element should be some
+valid <a href="http://www.w3.org/TR/html5/text-level-semantics.html#the-time-element">time value</a>.
+with an attribute can also be used is used in cases where the object is an
+IRI. Two more examples are found in lines 8 and 15. If the object of
+the triple is a literal, then RDFa uses the
+<code>property</code> attribute to specify the RDF property IRI. Lines
+4-5 and 14 contain examples of such triples. A <code>datatype</code>
+attribute is used to indicate the datatype of the literal (line 5). If
+no datatype or language tag is specified the literal is assumed to
+have the datatype <code>xsd:string</code> (line 14). </p>
+
+<p>Two more RDFa attributes appear in the example. The
+<code>typeof</code> attribute in line 1 is similar to the Turtle
+shorthand <code>a</code>: it signals the RDF class to which the IRI
+belongs. The <code>rev</code> ("reverse") attribute in line 17 signals
+that the triple specified should be interpreted in the reverse
+order: the "about" IRI is the object of the triple; the "href"
+attribute specifies the subject. </p>
+
+<p>For more information consult the RDFa Primer [[RDFA-PRIMER]] for detailed information about RDFa. </p>
+
+</section>
+
+<section id="section-rdfxml">
+
+<h3>RDF/XML</h3>
+
+<p>RDF/XML [[RDF-SYNTAX-GRAMMAR]] provides an XML syntax for RDF
+graphs. When RDF was original developed in the late 1990s, this was its
+only syntax, and some people still call this syntax "RDF". In 2001, a
+precursor to Turtle called "N3" was proposed, and gradually the other
+syntaxes listed here have been adopted and standardized. </p>
+
+<p>The RDF/XML example below encodes the
+RDF graph depicted in <a href="#fig4">Fig. 4</a>:</p>
+
+<pre class="example" id="rdf-xml-example">
+01 <?xml version="1.0" encoding="utf-8"?>
+02 <rdf:RDF
+03 xmlns:dcterms="http://purl.org/dc/terms/"
+04 xmlns:foaf="http://xmlns.com/foaf/0.1/"
+05 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+06 xmlns:schema="http://schema.org/">
+07 <rdf:Description rdf:about="http://example.org/bob#me">
+08 <rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
+09 <schema:birthDate rdf:datatype="http://www.w3.org/2001/XMLSchema#date">1990-07-04</schema:birthDate>
+10 <foaf:knows rdf:resource="http://example.org/alice#me"/>
+11 <foaf:topic_interest rdf:resource="http://www.wikidata.org/entity/Q12418"/>
+12 </rdf:Description>
+13 <rdf:Description rdf:about="http://www.wikidata.org/entity/Q12418">
+14 <dcterms:title>Mona Lisa</dcterms:title>
+15 <dcterms:creator rdf:resource="http://dbpedia.org/resource/Leonardo_da_Vinci"/>
+16 </rdf:Description>
+17 <rdf:Description rdf:about="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">
+18 <dcterms:subject rdf:resource="http://www.wikidata.org/entity/Q12418"/>
+19 </rdf:Description>
+20 </rdf:RDF>
+</pre>
+
+<p>In RDF/XML RDF triples are specified within an XML element
+<code>rdf:RDF</code> (lines 2 and 20). The attributes of the
+<code>rdf:RDF</code> start tag (lines 3-6) provide a shorthand for writing down
+names of XML elements and attributes. The XML element
+<code>rdf:Description</code> (short for
+<code>http://www.w3.org/1999/02/22-rdf-syntax-ns#Description</code>)
+is used to define sets of triples that have as subject the IRI
+specified by the <code>about</code> attribute. The first description
+block (line 7-12) has four sub-elements. The name of the subelement is
+an IRI representing an RDF property, e.g., <code>rdf:type</code> (line 8). Here, each
+subelement represents one triple.
+In cases where the object of the triple is also an IRI
+the property subelement has no content and the object IRI is specified
+using the <code>rdf:resource</code> attribute (lines 8, 10-11, 15 and
+18). For example, line 10 corresponds to the triple:</p>
+
+<pre class="example">
+<http://example.org/bob#me> <http://xmlns.com/foaf/0.1/knows> <http://example.org/alice#me> .
+</pre>
+
+<p>When the object of the
+triple is a literal the literal value is entered as content of the
+property element (lines 9 and 14). The datatype is specified as
+attribute of the property element (line 9). If the datatype is
+omitted (line 14) and no language tag is present the literal is
+considered to have the datatype <code>xsd:string</code>.
+
+<p>The example shows the baseline syntax; please consult the RDF/XML
+document [[RDF11-XML]] for a more in-depth treatment of the syntax. It
+might seem strange that the attribute values contain full IRIs,
+despite the fact that for some of these namespace prefixes were
+defined. This is because these prefixes can only be used for XML
+element and attribute names. </p>
+
+</section>
</section>
@@ -1136,7 +1251,7 @@
available as part of the Linked
Data [[LINKED-DATA]] cloud. Datasets are being published and
interlinked on the Web using RDF, and many of them offer a
- querying facility through SPARQL [[!SPARQL11-OVERVIEW]]. Examples
+ querying facility through SPARQL [[SPARQL11-OVERVIEW]]. Examples
of such datasets used in the examples above include:</p>
<ul>
@@ -1221,158 +1336,12 @@
<section id="appendix-other-syntaxes" class="appendix">
-<h2>More examples of RDF syntaxes</h2>
+<h2>Additional JSON-LD Examoples</h2>
-<p>In <a href="#section-graph-syntax">Sec. 5</a> the
-Turtle family of RDF languages and JSON-LD were introduced.
-This appendix lists
-corresponding examples for two other RDF syntaxes, namely RDFa and
-RDF/XML. Also, more elaborate examples of JSON-LD are included.</p>
-
-<section id="appendix-rdfa">
-<h3>RDFa</h3>
-
- <p class="issue">Include comments/suggestions from Ivan</p>
-
-<p>RDFa is an RDF syntax for encoding RDF
-triples in an HTML document. The HTML example below encodes the
-RDF graph depicted in <a href="#fig4">Fig. 4</a>:</p>
-
-<pre class="example" id="rdfa-example">
-01 <body prefix="foaf: http://xmlns.com/foaf/0.1/
-02 schema: http://schema.org/
-03 dcterms: http://purl.org/dc/terms/">
-04 <div resource="http://example.org/bob#me" typeof="foaf:Person">
-05 <p>
-06 Bob knows <a property="foaf:knows" href="http://example.org/alice#me">Alice</a>
-07 and was born on the <time property="schema:birthDate">1990-07-04</time>.
-08 </p>
-09 <p>
-10 Bob is interested in <span property="foaf:topic_interest"
-11 resource="http://www.wikidata.org/entity/">the Mona Lisa</span>.
-12 </p>
-13 </div>
-14 <div resource="http://www.wikidata.org/entity/">
-15 <p>
-16 The <span property="dcterms:title">Mona Lisa</span> was painted by
-17 <a property="dcterms:creator" href="http://dbpedia.org/resource/Leonardo_da_Vinci">Leonardo da Vinci</a>
-18 and is the subject of the video
-19 <a href="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">'La Joconde à Washington'</a>.
-20 </p>
-21 </div>
-22 <div resource="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">
-23 <link property="dcterms:subject" href="http://www.wikidata.org/entity/Q12418">
-24 </div>
-25 </body>
-</pre>
-
-<p>RDFa introduces a number of special attributes that enable the
-specification of triples within HTML. For example, the <code>div</code> elements
-in lines 4 and 14 have a <code>resource</code>
-attribute, specifying the IRI about which RDF statements can be made within this
-block. In line 6 we see a <code>property</code> attribute; the value
-of this attribute is interpreted as an RDF property IRI. The property
-is specified as an attribute of an <code>a</code> element; the
-<code>href</code> attribute value is interpreted here as the object of the
-triple. This results in the triple: <p>
-
-<pre class="example">
-<http://example.org/bob#me> <http://xmlns.com/foaf/0.1/knows> <http://example.org/alice#me> .
-</pre>
-
-<p>In line 7 we see a triple with as object a literal value. The
-<code>property</code> attribute is specified here on the HTML
-<code>time</code> element. HTML requires that the content of the time element should be some
-valid <a href="http://www.w3.org/TR/html5/text-level-semantics.html#the-time-element">time value</a>.
-with an attribute can also be used is used in cases where the object is an
-IRI. Two more examples are found in lines 8 and 15. If the object of
-the triple is a literal, then RDFa uses the
-<code>property</code> attribute to specify the RDF property IRI. Lines
-4-5 and 14 contain examples of such triples. A <code>datatype</code>
-attribute is used to indicate the datatype of the literal (line 5). If
-no datatype or language tag is specified the literal is assumed to
-have the datatype <code>xsd:string</code> (line 14). </p>
+<p>This appendix lists
+some more JSON-LD examples. </p>
-<p>Two more RDFa attributes appear in the example. The
-<code>typeof</code> attribute in line 1 is similar to the Turtle
-shorthand <code>a</code>: it signals the RDF class to which the IRI
-belongs. The <code>rev</code> ("reverse") attribute in line 17 signals
-that the triple specified should be interpreted in the reverse
-order: the "about" IRI is the object of the triple; the "href"
-attribute specifies the subject. </p>
-
-<p>For more information consult the RDFa Primer [[RDFA-PRIMER]] for detailed information about RDFa. </p>
-
-</section>
-
-<section id="appendix-rdfxml">
-
-<h3>RDF/XML</h3>
-
-<p>RDF/XML [[RDF11-XML]] is an XML syntax for RDFD. When RDF was
-original developed in the late 1990s, RDF/XML was its only syntax for
-RDF. The RDF/XML example below encodes the
-RDF graph depicted in <a href="#fig4">Fig. 4</a>:</p>
-<pre class="example" id="rdf-xml-example">
-01 <?xml version="1.0" encoding="utf-8"?>
-02 <rdf:RDF
-03 xmlns:dcterms="http://purl.org/dc/terms/"
-04 xmlns:foaf="http://xmlns.com/foaf/0.1/"
-05 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
-06 xmlns:schema="http://schema.org/">
-07 <rdf:Description rdf:about="http://example.org/bob#me">
-08 <rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person"/>
-09 <schema:birthDate rdf:datatype="http://www.w3.org/2001/XMLSchema#date">1990-07-04</schema:birthDate>
-10 <foaf:knows rdf:resource="http://example.org/alice#me"/>
-11 <foaf:topic_interest rdf:resource="http://www.wikidata.org/entity/Q12418"/>
-12 </rdf:Description>
-13 <rdf:Description rdf:about="http://www.wikidata.org/entity/Q12418">
-14 <dcterms:title>Mona Lisa</dcterms:title>
-15 <dcterms:creator rdf:resource="http://dbpedia.org/resource/Leonardo_da_Vinci"/>
-16 </rdf:Description>
-17 <rdf:Description rdf:about="http://data.europeana.eu/item/04802/243FA8618938F4117025F17A8B813C5F9AA4D619">
-18 <dcterms:subject rdf:resource="http://www.wikidata.org/entity/Q12418"/>
-19 </rdf:Description>
-20 </rdf:RDF>
-</pre>
-
-<p>In RDF/XML RDF triples are specified within an XML element
-<code>rdf:RDF</code> (lines 2 and 20). The attributes of the
-<code>rdf:RDF</code> start tag (lines 3-6) provide a shorthand for writing down
-names of XML elements and attributes. The XML element
-<code>rdf:Description</code> (short for
-<code>http://www.w3.org/1999/02/22-rdf-syntax-ns#Description</code>)
-is used to define sets of triples that have as subject the IRI
-specified by the <code>about</code> attribute. The first description
-block (line 7-12) has four sub-elements. The name of the subelement is
-an IRI representing an RDF property, e.g., <code>rdf:type</code> (line 8). Here, each
-subelement represents one triple.
-In cases where the object of the triple is also an IRI
-the property subelement has no content and the object IRI is specified
-using the <code>rdf:resource</code> attribute (lines 8, 10-11, 15 and
-18). For example, line 10 corresponds to the triple:</p>
-
-<pre class="example">
-<http://example.org/bob#me> <http://xmlns.com/foaf/0.1/knows> <http://example.org/alice#me> .
-</pre>
-
-<p>When the object of the
-triple is a literal the literal value is entered as content of the
-property element (lines 9 and 14). The datatype is specified as
-attribute of the property element (line 9). If the datatype is
-omitted (line 14) and no language tag is present the literal is
-considered to have the datatype <code>xsd:string</code>.
-
-<p>The example shows the baseline syntax; please consult the RDF/XML
-document [[RDF11-XML]] for a more in-depth treatment of the syntax. It
-might seem strange that the attribute values contain full IRIs,
-despite the fact that for some of these namespace prefixes were
-defined. This is because these prefixes can only be used for XML
-element and attribute names. In practice, developers use XML entity
-declarations to provide also shorthands for attribute vales. </p>
-
-</section>
<section id="appendix-jsonld">