Переход от XML документов к RDF документам. Цель языка RDF Целью языка RDF (Resource Description Framework) является...

XML RDF

RDF RDF (Resource Description Framework) -. XML , (specifies data) (China's Yangtze river):

XML RDF

RDF (2)

RDF

value value ...

RDF : , XML RDF ?": : RDF , XML (): , (), .RDF () ... () .RDF XML . RDF (regular), (recurring) . XML , RDF (non-RDF-compliant XML designs). ! : XML , XML . RDF (inferencing) .

RDF Semantic Web!

RDF : RDF , XML (, XML ).RDF (), . (namespaces). XML : RDF RDF.

, RDF () . RDF , ,

6300 kilometers western China's Qinghai-Tibet Plateau East China Sea

. .

rdf:ID rdf:ID URI". URI" URL XML "#, rdf:ID, ,

xml:base , URL URI . : URL . URI , :

rdf:about URI ( URI), . , rdf:ID, rdf:about:


= (--)

RDF = ! RDF XML (resource/property/value)! (, length 6300 .). , , (, -A Resource-B, -B Resource-C). , .

Value-C

-A -BNotice that the RDF design pattern is analternating sequence of resource-property.

This pattern is known as "striping".

(class) (property). (striping pattern).


RDF ():

rdf:Description + rdf:type XML. , - , , (class) :


: (Description) http://www.china.org/geography/rivers#Yangtze. ()River. http://www.china.org/geography/rivers#Yangtze (length) 6300 kilometers, startingLocation - western China's Qinghai-Tibet Plateau, endingLocation - East China Sea.": . , . RDF , .

rdf:ID, rdf:about, :


!




: RDF .

RDF : (Subject) , . (Predicate) , (). (Object) , ().

RDF (Parser) RDF web- W3C:http://www.w3.org/RDF/Validator/This RDF parser will tell you if your XMLis in the proper RDF format.

#2

6300 kilometers western China's Qinghai-Tibet Plateau East China Sea The Three Gorges Dam 1.5 miles 610 feet $30 billion

Yangtze2.xml XML , , RDF:

()RiverDam: Yangtze:lengthstartingLocationendingLocation: ThreeGorges:namewidthheightcost

Dam


Dam () . River, - length, startingLocation endingLocation. , River - Dam. . RDF . ( , RDF XML .)

6300 kilometersValue is a Literal The Three Gorges Dam 1.5 miles 610 feet $30 billion

XML ( RDF)


Yangtze2,v2.xml (river) Yangtze (obstacle), (Dam) ThreeGorges. (Dam) (name) - The Three Gorges Dam. 1.5 miles, 610 feet $30 billion."

RDF ()


Three-Gorges-Dam.rdf , - , Three Gorges Dam:Yangtze.rdf Three Gorges Dam rdf:resource, :

, , - , ,http://www.china.org/geography/rivers#Yangtze, RDF , . (aggregator tool) . !

rdf:ID rdf:about ? rdf:ID? rdf:about?When you want to introduce a resource, and provide an initial set of information about a resource use rdf:IDWhen you want to extend the information about a resource use rdf:aboutThe RDF philosophy is akin to the Web philosophy. That is, anyone, anywhere, anytime can provide information about a resource.


http://www.china.org/geography/rivers/yangtze.rdf

Dri Chu - Female Yak River Tongtian He, Travelling-Through-the-Heavens River Jinsha Jiang, River of Golden Sand

http://www.encyclopedia.org/yangtze-alternate-names.rdf

6300 kilometers western China's Qinghai-Tibet Plateau East China Sea Dri Chu - Female Yak River Tongtian He, Travelling-Through-the-Heavens River Jinsha Jiang, River of Golden Sand

Aggregated Data! (aggregator tool) YangtzeA distributed network of data!

The Three Gorges Dam 1.5 miles 610 feet $30 billion


http://www.china.org/geography/rivers/yangtze.rdfhttp://www.encyclopedia.org/three-gorges-dam.rdf


Aggregate!, ThreeGorges Dam , !

#3

Yangtze 6300 kilometers western China's Qinghai-Tibet Plateau East China Sea

, XML :Yangtze3.xmlXML


Yangtze3.rdfRDF RDF XML !

RDF


Yangtze3.rdfThis is read as: "This is an instance of the River type (class). The River has aname of Yangtze, a length of 6300 kilometers, a startingLocation of western China's Qinghai-Tibet Plateau, and an endingLocation of the East China Sea." .


http://www.china.org/geography/rivers/yangtze.rdf

Yangtze Dri Chu - Female Yak River Tongtian He, Travelling-Through-the-Heavens River Jinsha Jiang, River of Golden Sand

http://www.encyclopedia.org/yangtze-alternate-names.rdfAn aggregator tool will not be able to determine if these documents are talking about the same resource.Aggregate

#4Yangtze4.xmlYangtze4.rdf


RDF

6300 western China's Qinghai-Tibet Plateau East China Sea

Yangtze4.xmlRDF does not allow attributes on the properties (except for special RDF attributes such as rdf:resource). So we need to make the uom:units attribute a child element.Your first instinct might be to modify length to have two child elements:

rdf:valuelength6300kilometerslength has two values - 6300 and kilometers.RDF provides a special property, rdf:value, tobe used for specifying the "primary" value.In this example, 6300 is the primary value, andkilometers is a value which provides additionalinformation about the primary value.

RDF


Yangtze4.rdfAn anonymousresourceRead this as: "The Yangtze River has a length whose value is a resourcewhich has a value of 6300 and whose units is kilometers.

RDF An anonymous resource (also called a "blank node"). That is, a resource with no identifier. (Note: RDF Parsers will typicallygenerate a unique identifier for anonymous resources, todistinguish one anonymous resource from another.)Legend:

rdf:parseType="Resource"


Yangtze4,v2.rdfIf the value of a property is comprised of several values then one option is to create an anonymous resource, as we saw. RDF provides a shorthand,so that you don't need to create an rdf:Description element, by using rdf:parseType="Resource", as shown here:The meaning of this is identical to that shown on the previous slide.

!

6300 kilometers

6300 kilometers

XML , (valid) RDF :

6300 western China's Qinghai-Tibet Plateau East China Sea The Three Gorges Dam 1.5 miles 610 feet $30 billion

Yangtze.xml -->

#5

6300 kilometers 175 meters 55 kilometers

Yangtze5.rdfThis is one way of doing it.Now we will see a betterway - using "typed literals".(See next slide)

RDF

6300 175 55

Yangtze5.rdfWith rdf:datatype you can give a property's value a datatype label. Therdf:datatype value acts as a semantic label for the datatype of the value.This is called a typed literal.

For this example there must be a namespace, http://www.uom.org/distance#,which defines two datatypes - kilometer and meter.

On the next slide is shown how to do this using XML Schemas.

(datatypes) kilometer meter XML Schemas

uom.xsd

rdf:datatype

30

In this example we are specifying that the value (30) of age is a nonNegativeInteger (which is defined in the XML Schema namespace).

#6

-2 degrees Celsius 30.4 (rising) USA Massachusetts Boston January 22, 2003, 11:15 EST

WMUR_TV_WeatherReading.xml XML , , (valid) RDF :

1. XML ():2. 3 . , . ? - , . - Boston. Location.

1:


WMUR_TV_WeatherReading,v2.xml

2: Weather LocationTypes (classes) contain properties. We need to wrap the Weather and Locationtypes within a property:


WMUR_TV_WeatherReading,v3.xml

RDF !


WMUR_TV_WeatherReading.rdf

() rdf:BagThe rdf:Bag type is used to represent an unordered collection.

#7

John Smith Sally Jones

XML , , (valid) RDF :DesignMeeting.xmlrdf:Bag makes it clear that this is an unorderedcollection of names.


DesignMeeting.rdf

() rdf:Alt rdf:Alt .

() rdf:SeqThe rdf:Seq type is used to represent a sequence of properties.

rdf:li rdf:li ("list item") RDF rdf:Bag, rdf:Alt rdf:Seq.The rdf:li property is provided for you to specify an item in a Bag/Alt/Seq.An RDF Parser will replace each rdf:li with rdf:_1, rdf:_2, rdf:_3, etc.The following slide recasts the previous examples using the rdf:li property.

Meet with CEO at 10am Luncheon at The Eatery Flight at 3pm

MyDaysActivities.rdf

http://www.bn.com http://www.barnesandnoble.com

BarnesAndNoble.rdf


DesignMeeting.rdf

#10 XML , , (valid) RDF :

Lateral Thinking Edward de Bono 1973 0-06-099325-2 Harper & Row Illusions: The Adventures of a Reluctant Messiah Richard Bach 1977 0-440-34319-4 Dell Publishing Co. The First and Last Freedom J. Krishnamurti 1954 0-06-064831-7 Harper & Row

Barnes_and_Noble _BookCatalogue.xmlNote: regrettably,the Dublin Core doesnot conform to theRDF naming conventions. Hence,you see propertieswith the first lettercapitalized.

1. The XML document uses two types (classes):2. All type instances are anonymous. Consequently, we cannot benefit from others, and others cannot benefit from us. Where does it make sense to give the instance an identifier? - In general, the root element should have an identifier. - There is lots of information about each book instance. Let's give each book instance an identifier (the ISBN).

1:

Lateral Thinking Edward de Bono 1973 Harper & Row Illusions: The Adventures of a Reluctant Messiah Richard Bach 1977 Dell Publishing Co. The First and Last Freedom J. Krishnamurti 1954 Harper & Row

Barnes_and_Noble _BookCatalogue,v2.xmlNotice that the ISBN elements were deleted and their values used as identifiers.Why was an underscoreplaced in front of theISBN?Answer: The ID datatypedoes not allow an identifier to begin witha digit. So, we (arbitrarily) decided touse an underscore.

2: BookBarnes_and_Noble _BookCatalogue,v3.xml

Dublin Core (dc:)Dublin Core :Note: many people use these properties in their HTML today. For example:

rdf:parseType="Collection"This may be added as an attribute of a property to indicate that the contents of the property is a list of resources.The following slide recasts the BookCatalogue example to use this list type.

Lateral Thinking Edward de Bono 1973 Harper & Row Illusions: The Adventures of a Reluctant Messiah Richard Bach 1977 Dell Publishing Co. ...

Barnes_and_Noble_BookCatalogue.rdf

rdf:parseType="Literal"In all of the previous examples the data was structured as resource/property/value triples.Sometimes it doesn't make sense to do such structuringExample: with mixed contentIn those cases we can simply indicate "hey, the content of this property is okay. Treat it as a literal XML string."

Dangers of rdf:parseType="Literal"The advantage of structuring your XML as resource/property/value triples is enhanced interoperability.When you use rdf:parseType="Literal" you lose the ability for a tool to instantly take advantage of the resource/property/value structure (since you are, by definition, saying that the data doesn't have this structure).Lesson Learned: use rdf:parseType="Literal" sparingly!

#12

XMLRDFYangtze.xmlYangtze.rdf XML , , (valid) RDF :Note that attributes arebeing used, not childelements!The RDF format allowsyou to use attributes aswell!

Recall that at the very beginning of this tutorial we said that a resource has properties (attributes). Thus, a property can be represented either as a child element, or as an attribute. (Of course, a property can only be represented as an attribute if it has a literal value, not a structured value.)

Equivalent!


John Smith 555-1212 [email protected] 1995-01-01 1999-01-01 researcher Some Corp http://www.company.org Cool stuff

Oracle 13 Java 3 BS RPI 1987

, , XML" RDF. RDF XML . XML RDF ( XML ).

http://www.xml.com/pub/a/2002/10/30/rdf-friendly.html"Make Your XML RDF-Friendly" by Bob DuCharme, John Cowan

Identifies the type (class) of the resource being described.

resource/property/valueAnyone, Anywhere, Anytime Can Talk About a Resource

Переход от XML документов к RDF документам. Цель языка RDF Целью языка RDF (Resource Description Framework) является...

Documents

id rdf

description rdf

rdf inferencing

rdf regular

xml rdfrdf rdf

rdf xml resourcepropertyvalue

gorges dam rdf

river dam rdf