BULK RDF namespace
draft-thierry-bulk-rdf-00

Abstract

This specification describes a BULK serialization of RDF ontologies and graphs.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on February 07, 2014.

Copyright Notice

Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 1.1. Conventions and Terminology
• 2. BULK RDF namespace
• 2.1. URI reference
• 2.2. Base URI
• 2.3. URI prefix
• 2.4. blank
• 2.5. RDF literals
• 2.5.1. Plain literal
• 2.5.2. Typed literal
• 2.5.3. XMLLiteral
• 2.6. Triples
• 2.7. Turtle-like statements
• 2.8. RDF vocabulary
• 2.9. RDF embedding
• 3. Security Considerations
• 4. References
• 4.1. Normative References
• 4.2. Informative references
• Appendix A. Example: RDF Schema vocabulary
• Author's Address

1. Introduction

1.1. Conventions and Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

Literal numerical values are provided in decimal or hexadecimal as appropriate. Hexadecimal literals are prefixed with 0x to distinguish them from decimal literals.

BULK bytes sequences and expressions are described with the same conventions than used in the BULK 1.0 specification [BULK1]

2. BULK RDF namespace

The RDF namespace is an official namespace identified by the UUID urn:uuid:ed460331-a89b-5742-a8de-907dff727779 (BULK, "http://www.w3.org/1999/02/22-rdf-syntax-ns#"). Its first purpose is to serialize both RDF ontologies and graphs, but as RDF is deeply rooted in the World Wide Web and the REST architecture, some of the names and forms defined in this specification are intended to be used in applications related to those.

This specification defines the type URIString, which is an array whose content is a string conforming to the "URI-reference" production in [RFC3986] (section 4.1).

2.1. URI reference

name

0x1 (mnemonic: uriref )

shape

( uriref URIString )

This form makes it possible to differentiate a string containing a URI from a URI reference itself.

Type: URIRef

2.2. Base URI

name

0x2 (mnemonic: base )

shape

( base URIString )

This form changes the current base URI for URI resolution. If the given URI is relative, it must be resolved with the current base URI.

2.3. URI prefix

name

0x3 (mnemonic: prefix )

shape

( prefix {uri} )

Name's type

EagerFunction

Form's type

EagerFunction

Form's value

a function that returns a URIRef whose content is the concatenation of {uri} and its only argument (or returns {uri} if called without arguments)

{uri} can be of type URIString or URIRef. If it is of type URIRef, the above description should be taken as if the form is of shape ( prefix ( uriref {uri} ) ).

2.4. blank

name

0x4 (mnemonic: blank )

shape

( blank )

Name's type

EagerFunction

Form's type

Expr

Form's value

a new blank node. If a same blank node must be used in several forms, it should be made the value of a name.

2.5. RDF literals

Literals are arbitrary data that can be an object in an RDF triple. It is important to note that their BULK serialization doesn't need to denote the string of their lexical form.

Any array used as object in an RDF triple has the semantics of a plain literal without language tag.

2.5.1. Plain literal

name

0x5 (mnemonic: plain )

shape

( plain {lang}:Array {literal}:Array )

This is a plain RDF literal. {lang} is the language tag.

2.5.2. Typed literal

name

0x6 (mnemonic: type )

shape

( type {id}:URIRef {literal} )

This is a typed RDF literal. {id} is the datatype URI. Each type defines what is legal as {literal}.

2.5.3. XMLLiteral

name

0x7 (mnemonic: xmlliteral )

value

( uriref "http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral" )

A literal with this type SHOULD contain a BULK serialization of XML (cf. [BULK-XML]). An application MUST NOT use an array for this literal for anyhting else than a string that belongs to the lexical space defined for http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral.

2.6. Triples

name

0x8 (mnemonic: triples )

shape

( triples {triples} )

{triples} must be a sequence of ( {subj}:URIRef {pred}:URIRef {obj} ).

2.7. Turtle-like statements

name

0x9 (mnemonic: turtle )

shape

( turtle {statements} )

{statements} MUST be a sequnce of ( {subj}:URIRef {preds} ), where {preds} MUST be a sequence of ( {pred}:URIRef {objs} ), where {objs} is a sequence.

2.8. RDF vocabulary

The following names are associated with uriref forms, with a base URI of http://www.w3.org/1999/02/22-rdf-syntax-ns#. Their mnemonic is the lowercased URI reference.

2.9. RDF embedding

name

0x20 (mnemonic: this-resource )

shape

this-resource

This expression is intended to help embedding RDF metadata alongside or within a resource. It has the semantics of a blank node that designates this resource. What makes a resource the current described resource is application-dependent.

3. Security Considerations

4. References

4.1. Normative References

4.2. Informative references

Appendix A. Example: RDF Schema vocabulary

Here is the text notation of a BULK stream defining references for each element in the RDF Schema vocabulary. The whole stream is 444 bytes in length.

( bulk:version 1 0 )
( bulk:ns 32 rdf )
( bulk:ns* 33 rdfs )
( define rdfs:schema ( prefix "http://www.w3.org/2000/01/rdf-schema#" ) )
( define rdfs:resource ( rdfs:schema "Resource" ) )
( define rdfs:class ( rdfs:schema "Class" ) )
( define rdfs:subclassof ( rdfs:schema "subClassOf" ) )
( define rdfs:subpropertyof ( rdfs:schema "subPropertyOf" ) )
( define rdfs:comment ( rdfs:schema "comment" ) )
( define rdfs:label ( rdfs:schema "label" ) )
( define rdfs:domain ( rdfs:schema "domain" ) )
( define rdfs:range ( rdfs:schema "range" ) )
( define rdfs:seealso ( rdfs:schema "seeAlso" ) )
( define rdfs:isdefinedby ( rdfs:schema "isDefinedBy" ) )
( define rdfs:literal ( rdfs:schema "Literal" ) )
( define rdfs:container ( rdfs:schema "Container" ) )
( define rdfs:containermembershipproperty ( rdfs:schema "ContainerMembershipProperty" ) )
( define rdfs:member ( rdfs:schema "member" ) )
( define rdfs:datatype ( rdfs:schema "Datatype" ) )
( define rdfs:schema* ( rdfs:schema ) )
	

Here is the text notation of a BULK stream containg a small part of the RDF Schema ontology. The whole stream is 375 bytes in length (the corresponding RDF/XML document would be 1525 bytes in length).

( bulk:version 1 0 )
( bulk:ns 32 rdf )
( bulk:ns 33 rdfs )
( turtle
  ( rdfs:resource
    ( rdf:type rdfs:class )
    ( rdfs:isdefinedby rdfs:schema* )
    ( rdfs:label "Resource" )
    ( rdfs:comment "The class resource, everything." ) )
  ( rdfs:class
    ( rdf:type rdfs:class )
    ( rdfs:isdefinedby rdfs:schema* )
    ( rdfs:label "Class" )
    ( rdfs:comment "The class of classes." )
    ( rdfs:subclassof rdfs:resource ) )
  ( rdfs:subclassof
    ( rdf:type rdf:property )
    ( rdfs:isdefinedby rdfs:schema* )
    ( rdfs:label "subClassOf" )
    ( rdfs:comment "The subject is a subclass of a class." )
    ( rdfs:range rdfs:class )
    ( rdfs:domain rdfs:class ) )
  ( rdfs:subpropertyof
    ( rdf:type rdf:property )
    ( rdfs:isdefinedby rdfs:schema* )
    ( rdfs:label "subPropertyOf" )
    ( rdfs:comment "The subject is a subproperty of a property." )
    ( rdfs:range rdf:property )
    ( rdfs:domain rdf:property ) ) )
	

Author's Address