Differences

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--- rdf [2018/08/20 20:53]
christian [Experience]
+++ rdf [2018/08/20 21:02]
christian [Triple store]
@@ Line 25: / Line 25: @@
 The namespace is RDF. The core classes are
   * **Graph** is a collection of ''**Statement**''s
-  * **Statement** consists of subject, predicate and object; each of which is a ''**Term**''
+  * **Statement** consists of ''subject'', ''predicate'' and ''object''; each of which is a ''**Term**''
   * **Term** with ''**IRI**'', ''**Blank**'' and ''**Literal**'' as concrete subclasses
@@ Line 79: / Line 79: @@
 ==== XMP ====
-For the PDFtalk library I need XMP to work with the metadata of documents. XMP is a RDF language which restricts the very general RDF. Certain features are forbidden in XMP - luckily the complicated ones: ''**XMLLiterals**'' and ''**xml:base**''. Other restrictions apply to properties and how they are used. This defines the semantics of the language.
+For the PDFtalk library I need XMP to work with the metadata of documents. XMP is a RDF language which restricts the very general RDF. Certain features are forbidden in XMP - luckily the complex ones: ''XMLLiterals'' and ''xml:base''. Other restrictions apply to properties and how they are used. This defines the semantics of the language.
 I wonder how to do this: defining a language on RDF. Interesting task.
 ==== Triple store ====
-Eventually, I want to store a lot of statements. For now, a ''**Graph**'' is just an ''**OrderedCollection**'' of ''**Statement**''s. This will not be sufficient for large amounts of data. I will need a [[https://en.wikipedia.org/wiki/Triplestore|triplestore]].
+Eventually, I want to store a lot of statements. For now, a ''Graph'' is just an ''OrderedCollection'' of ''Statement''s. This will not be sufficient for large amounts of data. I will need a [[https://en.wikipedia.org/wiki/Triplestore|triplestore]].
 === Other syntaxes: Turtle and SPARQL ===
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 === Schemas and inferencing ===
-Schemas (or Vocabularies or ontologies) for RDF can be easily (?) defined by anyone. A schema itself is defined in RDF. Commonly used (and sometimes mixed) are RDFS (RDF Schema) and OWL (Web Ontology Language). Besides concepts like ''**Class**'' and ''**Property**'', predicates and value restrictions, an ontology also defines properties for relationships. For example you can define that the relation ''**married**'' between two persons is symetrical; or that the ''**subclass**'' relationship is transitive.
+Schemas (or Vocabularies or ontologies) for RDF can be easily (?) defined by anyone. A schema itself is defined in RDF. Commonly used (and sometimes mixed) are [[https://www.w3.org/TR/rdf-schema/|RDFS]] (RDF Schema) and [[https://www.w3.org/2001/sw/wiki/OWL|OWL]] (Web Ontology Language). Besides concepts like ''Class'' and ''Property'', predicates and value restrictions, an ontology also defines properties for relationships. For example you can define that the relation ''married'' between two persons is symetrical; or that the ''subclass'' relationship is transitive.
 With this, only basic facts have to be entered into a triple store. Many more facts can get deducted / inferenced. It would be an interesting project to build such an inferencer. I wonder if Gemstone would make a good triplestore.