- From: Seema Sundara <seema.sundara@oracle.com>
- Date: Tue, 05 Oct 2010 12:03:20 -0400
- To: RDB2RDF WG <public-rdb2rdf-wg@w3.org>
Seema Sundara wrote:
> Attached is the latest (5 Oct 2010) version of the FPWD that includes
> an example.
>
> Thanks
> Seema & Souri.
>
> Souripriya Das wrote:
>> I have attached a draft for the FPWD that Seema and I have prepared.
>> It is an html document.
>> Please take a look if you get a chance. We are still working on it.
>>
>> We hope to discuss this in our upcoming telcon.
>>
>> Thanks,
>> - Souri.
>>
>> On 10/1/2010 2:01 PM, Souripriya Das wrote:
>>> We have filled the initial portions of a W3C Working Draft template
>>> and at the moment working on putting the real content (the Schema
>>> and a (running) example). -- Souri.
>>>
>>> On 10/1/2010 11:06 AM, Michael Hausenblas wrote:
>>>> All,
>>>>
>>>> Below the agenda for our next week's meeting mainly discussing the
>>>> FPWD
>>>> "Relational Database to RDF Mapping Language" - Souri, Seema, and
>>>> Richard,
>>>> what's the status, there?
>>>>
>>>> Cheers,
>>>> Michael
>>>>
>>>> ---------------------------------------------------------
>>>> AGENDA Teleconference
>>>> W3C RDB2RDF Working Group telephone conference 2010-10-05
>>>> ----------------------------------------------------------
>>>> Tuesday, 5 October *16:00-17:00 UTC* Local time:
>>>> http://www.timeanddate.com/worldclock/fixedtime.html?month=10&day=05&year=20
>>>>
>>>> 10&hour=16&min=00&sec=0
>>>> Bridge US: +1-617-761-6200 (Zakim) Conference code : 7322733# (spells
>>>> "RDB2RDF")
>>>> Duration : 60 minutes
>>>> -------------------------------------------------------------------
>>>> IRC channel : #RDB2RDF on irc.w3.org:6665 W3C IRC Web Client :
>>>> http://www.w3.org/2001/01/cgi-irc
>>>> Zakim information : http://www.w3.org/2002/01/UsingZakim
>>>> Zakim bridge monitor : http://www.w3.org/1998/12/bridge/Zakim.html
>>>> Zakim IRC bot : http://www.w3.org/2001/12/zakim-irc-bot.html
>>>> -------------------------------------------------------------------
>>>>
>>>> Chair: Michael
>>>> Scribe: Zakim, pick a victim
>>>>
>>>>
>>>> 1. Admin
>>>> PROPOSAL: Accept the minutes of last meeting, see
>>>> http://www.w3.org/2010/09/28-rdb2rdf-minutes.html
>>>>
>>>> Review open actions, see
>>>> http://www.w3.org/2001/sw/rdb2rdf/track/actions/open
>>>>
>>>> 2. FPWD "Relational Database to RDF Mapping Language"
>>>> The editors (Souri, Seema, and Richard) will present the first draft.
>>>>
>>>> 3. Default Mapping Cases
>>>> http://www.w3.org/2001/sw/rdb2rdf/wiki/All_Cases_for_Default_Mapping
>>>>
>>>> 4. AOB
>>>>
>>>>
>>>> Cheers,
>>>> Michael
>>>>
>>>
>>>
>>
>>
>> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
>
> W3C <http://www.w3.org/>
>
>
> R2RML: RDB2RDF Mapping Language
>
>
> W3C Working Draft 5 October 2010
>
> This version:
>
> URL-to-be-created
> Editors:
> Souripriya Das, Oracle
> Seema Sundara, Oracle
> Richard Cyganiak, DERI, National University of Ireland, Galway,
> Ireland <richard@cyganiak.de> <mailto:richard@cyganiak.de>
>
> ------------------------------------------------------------------------
>
>
> Abstract
>
> RDF is a directed, labeled graph data format for representing
> information in the Web. This specification defines the syntax and
> semantics of the R2RML (RDB2RDF Mapping Language) for translating
> Relational data to RDF.
>
>
> Status of this Document
>
> /This section describes the status of this document at the time of its
> publication. Other documents may supersede this document. A list of
> current W3C publications and the latest revision of this technical
> report can be found in the //W3C technical reports index
> <http://www.w3.org/TR/> at http://www.w3.org/TR/./
>
> Publication as a Working Draft does not imply endorsement by the W3C
> Membership. This is a draft document and may be updated, replaced or
> obsoleted by other documents at any time. It is inappropriate to cite
> this document as other than work in progress.
>
> The documents produced by this Working Group are:
>
> * R2RML: RDB2RDF Mapping Language (this document)
>
> This publication includes the RDF Schema that can be used to specify a
> mapping of relational data to RDF. The structure of this document will
> change based upon future decisions taken by the W3C RDB2RDF Working Group.
>
> Comments on this document should be sent to
> public-rdb2rdf-comments@w3.org
> <mailto:public-rdb2rdf-comments@w3.org>, a mailing list with a public
> archive <http://lists.w3.org/Archives/Public/public-rdb2rdf-comments>.
>
> This document was produced by the RDB2RDF Working Group
> <http://www.w3.org/2001/sw/RDB2RDF/>, which is part of the W3C
> Semantic Web Activity <http://www.w3.org/2001/sw/Activity>.
>
> This document was produced by a group operating under the 5 February
> 2004 W3C Patent Policy
> <http://www.w3.org/Consortium/Patent-Policy-20040205/>. W3C maintains
> a public list of any patent disclosures
> <http://www.w3.org/2004/01/pp-impl/35463/status> made in connection
> with the deliverables of the group; that page also includes
> instructions for disclosing a patent. An individual who has actual
> knowledge of a patent which the individual believes contains Essential
> Claim(s)
> <http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential>
> must disclose the information in accordance with section 6 of the W3C
> Patent Policy
> <http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure>.
>
>
> Table of Contents
>
> 1 Introduction <#introduction>
> Â Â Â Â 1.1 Document Outline <#docOutline>
> Â Â Â Â 1.2 Document Conventions <#docConventions>
> Â Â Â Â Â Â Â Â 1.2.1 Namespaces <#docNamespaces>
> Â Â Â Â Â Â Â Â 1.2.2 Data Descriptions <#docDataDesc>
> Â Â Â Â Â Â Â Â 1.2.3 Terminology <#docTerminology>
> 2 Overview <#R2rmlOverview>
> 3 RDF Schema for R2RML <#R2rmlSchema>
> Â Â Â Â 3.1 RDFTermMap Class <#RDFTermMap_Class>
> Â Â Â Â Â Â Â Â 3.1.1 Properties of the RDFTermMap Class
> <#RDFTermMap_Properties>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.1 rr:property
> <#RDFTermMap_property_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.2 rr:column <#RDFTermMap_column_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.3 rr:inverseExpression
> <#RDFTermMap_inverseExpression_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.4 rr:datatype
> <#RDFTermMap_datatype_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.5 rr:language
> <#RDFTermMap_language_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.6 rr:columnGraph
> <#RDFTermMap_columnGraph_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.7 rr:constantValue
> <#RDFTermMap_constantValue_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.8 rr:isRDFType
> <#RDFTermMap_isRDFType_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.9 rr:isComputed
> <#RDFTermMap_isComputed_Property>
> Â Â Â Â 3.2 Subclasses of RDFTermMap Class <#RDFTermMap_Subclasses>
> Â Â Â Â Â Â Â Â 3.2.1 RDFSubjectTermMap Class <#RDFSubjectTerm>
> Â Â Â Â Â Â Â Â 3.2.2 IRIMap Class <#RDFIRI>
> Â Â Â Â Â Â Â Â 3.2.3 bNodeMap Class <#RDFBNODE>
> Â Â Â Â Â Â Â Â 3.2.4 LiteralMap Class <#RDFLiteral>
> Â Â Â Â 3.3 Table2TriplesMap Class <#Table2TriplesMap_Class>
> Â Â Â Â Â Â Â Â 3.3.1 Properties of the Table2TriplesMap Class
> <#Table2TriplesMap_Properties>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.1 rr:logicalTable
> <#T2TMap_logicalTable_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.2 rr:class <#T2TMap_class_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.3 rr:tableGraphMap
> <#T2TMap_tableGraphMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.4 rr:subjectMap
> <#T2TMap_subjectMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.5 rr:propertyObjectMap
> <#T2TMap_propertyObjectMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.3.1.6 rr:computedPropertyMap
> <#T2TMap_computedPropertyMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.7 rr:rowGraphPropertyMap
> <#T2TMap_rowGraphPropertyMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.1.1.8 rr:foreignKeyMap
> <#T2TMap_foreignKeyMap_Property>
> Â Â Â Â 3.4 ForeignKey Class <#ForeignKey_Class>
> Â Â Â Â Â Â Â Â 3.4.1 Properties of the ForeignKey Class
> <#ForeignKey_Properties>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.4.1.1 rr:key <#ForeignKey_key_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.4.1.2 rr:parentTable2TriplesMap
> <#ForeignKey_parentTable2TriplesMap_Property>
> Â Â Â Â Â Â Â Â Â Â Â Â 3.4.1.3 rr:joinCondition
> <#ForeignKey_joinCondition_Property>
>
>
> Appendices
>
> A References <#sec-bibliography>
> Â Â Â Â A.1 Normative References <#sec-normative-refs>
> Â Â Â Â A.2 Other References <#sec-non-normative-refs>
> B Example of SQL based RDB2RDF Mapping using the Turtle Syntax
> <#sec-example>
> Â Â Â Â B.1 Sample Relational Tables <#sec-tables>
> Â Â Â Â B.2 Mapping Specification for the Tables <#sec-mapping>
> Â Â Â Â Â Â Â Â B.2.1 Mapping Specification for the DEPT Table
> <#sec-depttable_mapping>
> Â Â Â Â Â Â Â Â B.2.2 Mapping Specification for the EMP Table
> <#sec-emptable_mapping>
> Â Â Â Â Â Â Â Â B.2.3 Mapping Specification for the LIKES Table
> <#sec-likestable_mapping>
> C CVS History <#sec-cvsLog>
>
> ------------------------------------------------------------------------
>
>
> 1 Introduction
>
> RDF is a directed, labeled graph data format for representing
> information in the Web. RDF is often used to represent, among other
> things, personal information, social networks, metadata about digital
> artifacts, as well as to provide a means of integration over disparate
> sources of information. The ability to view realtional data as RDF
> will allow integration of relational data from disparate sources. This
> specification defines the schema for mapping relational data to RDF
> using Turtle syntax.
>
> The R2RML language for mapping relational data to RDF is designed to
> meet the use cases and requirements identified by the RDB2RDF Working
> Group in Use Cases and Requirements
> [http://www.w3.org/2001/sw/rdb2rdf/wiki/Use_Cases_and_Requirements].
>
>
> 1.1 Document Outline
>
> Unless otherwise noted in the section heading, all sections and
> appendices in this document are normative.
>
> /@@Revise when structure stable/
>
> This section of the document, section 1 <#introduction>, introduces
> the R2RML specification. It presents the organization of this
> specification document and the conventions used throughout the
> specification.
>
> Section 3 <#R2rmlSchema> presents details of the RDFS schema for R2RML.
>
>
> 1.2 Document Conventions
>
>
> 1.2.1 Namespaces
>
> In this document, examples assume the following namespace prefix
> bindings unless otherwise stated:
>
> Prefix IRI
> |rdf:| |http://www.w3.org/1999/02/22-rdf-syntax-ns#|
> |rdfs:| |http://www.w3.org/2000/01/rdf-schema#|
> |xsd:| |http://www.w3.org/2001/XMLSchema#|
> |rr:| |http://www.w3.org/ns/r2rml#|
> |xyz:| |http://xyz.com/example#|
>
>
> 1.2.2 Data Descriptions
>
> This document uses the Turtle
> <http://www.w3.org/TeamSubmission/turtle/> [TURTLE <#TURTLE>] data
> format to show each triple explicitly. Turtle allows IRIs to be
> abbreviated with prefixes:
>
> @prefix dc: <http://purl.org/dc/elements/1.1/> .
> @prefix : <http://example.org/book/> .
> :book1 dc:title "R2RML Tutorial" .
>
>
> 1.2.3 Terminology
>
> The R2RML language includes IRIs, a subset of RDF URI References that
> omits spaces.
>
> The following terms are defined in RDF Concepts and Abstract Syntax
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/> [CONCEPTS]
> <#CONCEPTS> and used in R2RML:
>
> * IRI
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-URI-reference>
> (corresponds to the Concepts and Abstract Syntax term "|RDF URI
> reference|")
> * literal
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-literal>
> * lexical form <http://www.w3.org/TR/rdf-concepts/#dfn-lexical-form>
> * plain literal
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-plain-literal>
> * language tag
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-language-identifier>
> * typed literal
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-typed-literal>
> * datatype IRI
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-datatype-URI>
> (corresponds to the Concepts and Abstract Syntax term "|datatype
> URI|")
> * blank node
> <http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/#dfn-blank-node>
>
>
> 2 Overview
>
> The overall flow for mapping relational data to RDF may be summarized
> as follows:
>
> Given read-only access to a set of tables and/or views in a database,
> one can write a mapping of the content of some or all of these tables
> or views or any logical tables formed as SQL queries involving some of
> these tables and/or views to generate corresponding RDF triples.
> Besides generating triples, the mapping may also create an RDFS schema
> consisting of RDFS classes and RDF properties and RDF named graphs may
> be created for holding subsets of the generated triples.
>
> Note that the RDF triples may not actually be physically generated and
> instead the mapping may only allow the relational data to be viewed as
> RDF triples.
>
> The RDB2RDF Mapping Language, R2RML, described in this document,
> allows one to write a mapping to (virtually) generate a custom
> collection RDF graphs, named or unnamed, containing RDF triples, from
> a set of relational tables and/or views to which the user has (at
> least) read-only access.
>
>
> 3 RDF Schema for R2RML using Turtle Syntax
>
> This section describes the RDF Schema that can be used for specifying
> mapping from a relational schema to RDF.
>
>
> 3.1 RDFTermMap Class
>
> The RDFTermMap class reprersents the description of mapping to any RDF
> term: IRIs, blank nodes, or literals. This has two main components:
> mapping to an RDF property and mapping to an object value (to be
> associated with the property).
>
>
> 3.1.1 Properties of the RDFTermMap Class
>
> This section defines the RDF properties that have the RDFTermMap class
> as their domain.
>
>
> 3.1.1.1 rr:property property
>
> rr:property rdfs:range rdf:Resource .
>
> This property specifies the RDF property component of the RDFTermMap
> instance.
>
>
> 3.1.1.2 rr:column property
>
> rr:column rdfs:range xsd:string .
>
> This property specifies the object value component of the RDFTermMap
> instance. Specifically, the column name of the logical table that will
> be used for obtaining the object value.
>
>
> 3.1.1.3 rr:inverseExpression property
>
> rr:inverseExpression rdfs:range xsd:string .
>
> This optional property specifies an expression that allows, at query
> processing time, use of indexes on any (underlying) relational table
> when accessing based on a value of a column (defined as an expression)
> in the logical table.
>
> For example, for the deptId column in the logical table shown in
> Section 3.3.1.1, the inverse expression could be defined as follows:
>
> "{alias.}deptno = substr({alias.}deptId,length('dept')+1)"
>
> to facilitate use of an index on the deptno column of the dept table.
> Note that the actual alias (say d) used for the dept table is used to
> expand {alias.} (to d.).
>
>
> 3.1.1.4 rr:datatype property
>
> rr:datatype rdfs:range rdf:Resource .
>
> This property specifies the datatype for the object value component of
> the RDFTermMap instance.
>
>
> 3.1.1.5 rr:language property
>
> rr:language rdfs:range xsd:string .
>
> This property specifies the language for the object value component of
> the RDFTermMap instance. This property is applicable only if the
> datatype of the object value is of type xsd:string.
>
>
> 3.1.1.6 rr:columnGraph property
>
> rr:columnGraph rdfs:range rr:SubjectTermMap .
>
> This property specifies the RDF named graph for the triples that is
> constructed with the (property, object) pair of the RDFTermMap.
>
>
> 3.1.1.7 rr:constantValue property
>
> rr:constantValue rdfs:range xsd:string .
>
> This property specifies the optional constant value for the object
> component of the RDFTermMap instance.
>
>
> 3.1.1.8 rr:isRDFType property
>
> rr:isRDFType rdfs:range xsd:boolean .
>
> This property specifies if the object value component of the
> RDFTermMap instance is also a value for the rdf:type property.
>
>
> 3.1.1.9 rr:isComputed property
>
> rr:isComputed rdfs:range xsd:boolean .
>
> This property specifies if the object value component of the
> RDFTermMap instance is a computed property.
>
>
> 3.2 Subclasses of the RDFTermMap Class
>
> This section enumerates the subclasses of the RDFTermMap class. These
> classes describe the various types of RDF terms namely IRIs, blank
> nodes, and literals.
>
>
> 3.2.1 RDFSubjectTermMap
>
> The RDFSubjectTermMap class represents the mapping to any RDF term
> that can appear as subject of an RDF triple: IRIs or blank nodes.
>
> rr:RDFSubjectTermMap rdfs:subClassOf rr:RDFTermMap .
>
>
> 3.2.2 IRIMap
>
> The IRIMap class represents the mapping to a RDF Resource.
>
> rr:IRIMap rdfs:subClassOf rr:RDFSubjectTermMap .
>
>
> 3.2.3 bNodeMap
>
> The bNodeMap class represents the mapping to a RDF blank node.
>
> rr:bNodeMap rdfs:subClassOf rr:RDFSubjectTermMap .
>
>
> 3.2.4 LiteralMap
>
> The LiteralMap class represents the mapping to a RDF literal.
>
> rr:LiteralMap rdfs:subClassOf rr:RDFTermMap .
>
>
> 3.3 The Table2TriplesMap Class
>
> Table2TriplesMap is an RDFS class that allows specification of a
> mapping of the rows in a logical table, represented by a SQL query, or
> the name of a table or view and its owner, into RDF triples.
> Properties of a Table2TriplesMap instance allows specification of
> various aspects of the mapping such as, mapping of (some of) the
> columns in the logical table to RDF properties, name of the RDF
> graph(s) that would store the RDF triples, and so on.
>
>
> 3.3.1 Properties of the Table2TriplesMap Class
>
> This section defines the RDF properties that have the Table2TriplesMap
> class as their domain.
>
>
> 3.3.1.1 rr:logicalTable property
>
> rr:logicalTable rdfs:range xsd:String .
>
> This property specifies the logical table (i.e., a SQL query or a
> table or view name plus its owner name) whose rows are mapped to RDF
> triples by this Table2TriplesMap instance. Note that each row in the
> logical table is identified as a resource and is used as the subject
> for the RDF triples.
>
> The following example speifies that the Table2TriplesMap instance
> Table2TriplesMap1 maps the rows in the logical table defined by the
> SQL string to RDF triples.
>
> <#Table2TriplesMap1> rr:logicalTable
> """Select 'dept' || deptno AS deptId
> , deptno
> , dname
> , loc
> from dept""" .
>
> The cardinality of this property, for a Table2TriplesMap instance,
> must be exactly 1. That is, a Table2TriplesMap instance must have
> exactly one value for this property.
>
>
> 3.3.1.2 rr:class property
>
> rr:class rdfs:range rdfs:Class .
>
> This property specifies the RDFS class associated with a
> Table2TriplesMap instance. In the generated RDF data, resource
> corresponding to each row in the logical table is an instance of this
> RDFS class.
>
> In the following example, Table2TriplesMap1 is associated with the the
> RDFS class xyz:dept using rr:class. This leads to creation of xyz:dept
> as an RDFS class in the RDFS schema generated from the mapping
> specification and in the generated RDF data, RDF resource
> corresponding to each row in the logical table associated with
> Table2TriplesMap1 is an instance of the xyz:dept class.
> [@@ We need to discuss this to make it optional to generate xyz:dept
> as an RDFS class in the generated RDFS schema.]
>
> <#Table2TriplesMap1> rr:class xyz:dept .
>
>
> 3.3.1.3 rr:tableGraphMap property
>
> rr:tableGraphMap rdfs:range rdf:Resource .
>
> This property specifies the graph (IRI or blank node) that would
> contain all the RDF triples in a Table2TriplesMap instance.
>
> In the following example, all the RDF triples in Table2TriplesMap1
> would be stored in the RDF named graph xyz:DeptGraph.
>
> <#Table2TriplesMap1> rr:tableGraphMap xyz:DeptGraph .
>
>
> 3.3.1.4 rr:subjectMap property
>
> rr:subjectMap rdfs:range rr:RDFSubjectTermMap .
>
> This property specifies the mapping to obtain the IRI or blank node
> that is used as the subject of /all/ the RDF triples generated from
> /one/ row of the table.
>
>
> 3.3.1.5 rr:propertyObjectMap property
>
> rr:propertyObjectMap rdfs:range rr:RDFTermMap .
>
> This property specifies the mapping to obtain the (property, object)
> pair for each RDF triple corresponding to a column and its values in
> the table.
>
>
> 3.3.1.6 rr:computedPropertyMap property
>
> rr:computedPropertyMap rdfs:range rr:IRIMap .
>
> This property specifies the mapping to obtain the property IRIs from a
> column in the table. This mapping also contains a property name that
> identifies this computedPropertyMap and this property name is used in
> a rr:propertyObjectMap to form the association. The property IRI
> generated (from the column identified in the rr:computedPropertyMap)
> for each row, along with the value of the column identified in the
> rr:propertyObjectMap, are used to create the (property, object) pairs.
>
>
> 3.3.1.7 rr:rowGraphPropertyMap property
>
> rr:rowGraphPropertyMap rdfs:range rr:SubjectTermMap .
>
> This property specifies the mapping to obtain the IRI or blank node
> that identifies the RDF named graph for all the RDF triples generated
> from one row in the table. The minimum cardinality for this property
> is zero and no restriction on maximum cardinality. If for a row, the
> generated graph IRI or blank node label is NULL, then the triples
> generated from that row go to an unnamed graph.
>
>
> 3.3.1.8 rr:foreignKeyMap property
>
> rr:foreignKeyMap rdfs:range rr:ForeignKey .
>
> This property specifies the mapping to obtain the property, and a join
> condition that can be used to retrieve the object (from the parent
> Table2Triples instance), for the generated RDF triple. This property
> would typically correspond to a foreign key definition in the table.
>
>
> 3.4 The ForeignKey Class
>
> ForeignKey is an RDFS class that allows specification of the mapping
> that describes a foreign key relationship.
>
> rr:ForeignKey a rdfs:Class .
>
> This class has three components: a key that specifies the column
> constituting the constraint in the child table, the Table2TripleMap
> corresponding to the parent table, and the join condition
> corresponding to the foreign key constraint.
>
>
> 3.4.1 Properties of the ForeignKey Class
>
> This section defines the RDF properties that have the ForeignKey class
> as their domain.
>
>
> 3.4.1.1 rr:key property
>
> rr:key rdfs:range rdf:Resource .
>
> This property specifies the key component of the ForeignKey instance.
>
>
> 3.4.1.2 rr:parentTable2TriplesMap property
>
> rr:parentTable2TriplesMap rdfs:range rr:Table2TriplesMap .
>
> This property specifies the Table2TriplesMap corresponding to the
> parent table component, of the ForeignKey instance.
>
>
> 3.4.1.3 rr:joinCondition property
>
> rr:joinCondition rdfs:range xsd:string .
>
> This property specifies the join condition of the ForeignKey instance.
>
>
> A References
>
>
> A.1 Normative References
>
>
> A.2 Other References
>
>
> B Example of SQL based RDB2RDF Mapping using the Turtle Syntax
>
> In this section we show an example relational schema and then map the
> example schema to RDF using the Turtle syntax.
>
>
> B.1 Sample Relational Tables
>
> We illustrate our example with the use of the following three
> relational tables
>
>
> B.1.1 DEPT Table
>
> Column Name Column Datatype Column Key Constraints
> |deptno| |NUMBER| |UNIQUE|
> |dname| |VARCHAR2(30)|
> |loc| |VARCHAR2(100)|
>
>
> B.1.2 EMP Table
>
> Column Name Column Datatype Column Key Constraint
> |empno| |NUMBER| |PRIMARY KEY|
> |ename| |VARCHAR2(100)|
> |job| |VARCHAR2(30)|
> |deptno| |NUMBER| |REFERENCES DEPT(deptno)|
> |etype| |VARCHAR2(30)|
>
>
> B.1.3 LIKES Table
>
> Column Name Column Datatype Column Key Constraint
> |id| |VARCHAR2(4000)|
> |likeType| |VARCHAR2(30)|
> |likedObj| |VARCHAR2(100)|
>
>
> B.2 Mapping Specification for the Tables
>
> The tables specified in the above section are mapped to the RDF using
> the mapping specificied in this document. In addition to the prefix
> conventions specified in Section 1.2.1 Namespaces <#docNamespaces>
> , we also use the following prefixes in our example:
>
> Prefix IRI
> |emp:| |http://www.example.com/emp#|
> |dept:| |http://www.example.com/dept#|
> |likes:| |http://www.example.com/likes#|
>
>
> B.2.1 Mapping Specification for the DEPT Table
>
> <#Table2TriplesMap1>
> a rr:Table2TriplesMap;
> rr:logicalTable """
> Select 'dept' || deptno AS deptId
> , deptno
> , dname
> , loc
> from dept
> """;
> rr:class xyz:dept;
> rr:tableGraphMap xyz:DeptGraph;
> rr:subjectMap [ a rr:bNodeMap; rr:column "deptId";
> rr:InverseExpression "(alias.)deptno = substr({alias.}deptId,length('dept')+1)"];
> rr:propertyObjectMap [ a rr:LiteralMap; rr:datatype xsd:positiveInteger;
> rr:property dept:deptno; rr:column "deptno" ];
> rr:propertyObjectMap [ rr:property dept:name; rr:column "dname" ];
> rr:propertyObjectMap [ rr:property dept:location; rr:column "loc" ];
> rr:propertyObjectMap [ rr:property dept:COMPANY; rr:constantValue "XYZ Corporation" ];
> .
>
>
> B.2.2 Mapping Specification for the EMP Table
>
> <#Table2TriplesMap2>
> a rr:Table2TriplesMap;
> rr:logicalTable """
> Select 'xyz.com/emp/' || empno AS empURI
> , empno
> , ename
> , 'xyz.com/emp/job/'|| job AS jobTypeURI
> , job
> , deptno
> , 'xyz.com/emp/etype/'|| etype AS empTypeURI
> , etype
> , 'xyz.com/graph/'|| job || '/' || etype AS graphURI
> from emp
> """;
> rr:class xyz:emp;
> rr:subjectMap [ a rr:IRIMap; rr:column "empURI" ];
>
> rr:rowGraphPropertyMap [ rr:column "graphURI"; a rr:IRIMap];
>
> rr:propertyObjectMap [ rr:property emp:jobtype; rr:column "jobTypeURI"; rr:isRDFType "true"^^xsd:boolean];
> rr:propertyObjectMap [ rr:property emp:emptype; rr:column "empTypeURI"; rr:isRDFType "true"^^xsd:boolean];
>
> rr:propertyObjectMap [ rr:property emp:empno; rr:column "empno" ];
> rr:propertyObjectMap [ rr:property emp:name; rr:column "ename"; rr:columnGraph [ rr:constantValue "emp:empNameGraph"; a rr:IRIMap]];
> rr:propertyObjectMap [ rr:property emp:job; rr:column "job" ];
> rr:propertyObjectMap [ rr:property emp:deptNum; rr:column "deptno" ];
> rr:propertyObjectMap [ rr:property emp:etype; rr:column "etype" ];
> rr:foreignKeyMap [
> rr:key emp:c_ref_deptno;
> rr:parentTable2TriplesMap xyz:dept;
> rr:joinCondition "{child.}deptno = {parent.}deptno";
> ];
> .
>
>
> B.2.3 Mapping Specification for the LIKES Table
>
> <#Table2TriplesMap3>
> a rr:Table2TriplesMap;
> rr:logicalTable """
> Select id
> , likeType
> , likedObj
> from likes
> """;
> rr:class xyz:likes;
> rr:tableGraphMap xyz:LikesGraph;
> rr:subjectMap [ a rr:IRIMap; rr:column "id"];
> rr:ComputedPropertyMap [ rr:property likes:likeType; rr:column "likeType" ];
> rr:propertyObjectMap [ rr:property likes:likeType; rr:column "likedObj"; rr:isComputed "true"^^xsd:boolean];
> .
>
>
> C CVS History
>
> $Log: Overview.html,v $
>
> Revision 1.1 2010/09/29 15:27:28 sdas2/ssundara
> CREATED
>
>
Received on Tuesday, 5 October 2010 16:05:21 UTC