1 sunitha ramanujam 1, anubha gupta 1, latifur khan 1, steven seida 2, bhavani thuraisingham 1 1 the...

1

Sunitha Ramanujam1, Anubha Gupta1, Latifur Khan1, Steven Seida2, Bhavani Thuraisingham1

1The University of Texas at Dallas2Raytheon Company

*Funded by

Chris Bizer, Richard Cyganiak, Christian Becker, Andreas Langegger, Herwig Leimer

Freie Universität Berlin

AgendaD2RQ BasicsR2D (RDF-to-Database) Research

MotivationR2D System ArchitectureR2D Modules

RDFMapFileGeneratorDBSchemaGeneratorSQL-to-SPARQL Translation

Experimental ResultsConclusions & Future Work

2

Why D2RQ…Semantic Web Technologies are maturingGrowing need for RDF applications to access legacy

database content without replicating the entire database into RDF

What you can do with D2RQ…Query a non-RDF database using SPARQLAccess information in a non-RDF database using the Jena

APIAccess the contents of a non-RDF database as Linked

Data over the Web

What D2RQ is…Tool for publishing content of relational databases on the

Semantic WebConsists of

D2RQ Mapping LanguageD2RQ EngineD2RQ Server

D2RQ Mapping LanguageDeclarative language to express mappings between a

given RDF schemata and a relational schemata

D2RQ ClassMapRepresents a class or a group of similar classes of an

OWL ontology or RDFS Schema

map:employee a d2rq:ClassMap;

d2rq:dataStorage map:database;

d2rq:uriPattern "employee/@@employee.empid@@";

d2rq:class vocab:employee;

Empid Ename Deptid

12345 Nisha 10

23456 Meera 10

D2RQ PropertyBridgeRelates database table columns to RDF propertiesUsed to attach properties to the RDF resource created by a

class map

map:employee_empid a d2rq:PropertyBridge;

d2rq:belongsToClassMap map:employee;

d2rq:property vocab:employee_empid;

d2rq:column "employee.empid";

d2rq:datatype xsd:int;

D2RQ JoinsUsed to join tables in an n:m relationship

map:employee_deptid a d2rq:PropertyBridge;


d2rq:property vocab:employee_deptid;

d2rq:refersToClassMap map:department;

d2rq:join "employee.deptid = department.deptid";

Empid Ename Deptid

12345 Nisha 10

23456 Meera 10

Deptid Dname

10 Research

20 Accounts

Other Features of D2RQConditional Mappings

map:Paper a d2rq:ClassMap; d2rq:class :Paper;

d2rq:uriPattern "http://www.conference.org/conf02004/paper#Paper@@Papers.PaperID@@";d2rq:condition "Papers.Publish = 1"; d2rq:dataStorage map:Database1.

Translation Tables:red a :Color; :green a :Color;:blue a :Color;

map:ColorBridge a d2rq:PropertyBridge; d2rq:belongsToClassMap map:ShinyObjectMap; d2rq:property :color; d2rq:uriColumn "ShinyObject.Color"; d2rq:translateWith map:ColorTable.

map:ColorTable a d2rq:TranslationTable; d2rq:translation [ d2rq:databaseValue "R"; d2rq:rdfValue :red; ]; d2rq:translation [ d2rq:databaseValue "G"; d2rq:rdfValue :green; ]; d2rq:translation [ d2rq:databaseValue "B"; d2rq:rdfValue :blue; ].

D2RQ Command Line ToolsAuto-Generate Mapping Files: “generate-mapping” script

Creates a default mapping file by analyzing the schema of an existing database

Usage: generate-mapping [-u username] [-p password] [-d driverclass] [-o outfile.n3] jdbcURL

Example: generate-mapping -u root -p deekvish123 -d com.mysql.jdbc.Driver -o test.n3 jdbc:mysql://localhost/test

Sample Mapping File: test.n3@prefix map: <file:/C:/SUNITHA/D2RQ/D2RSER4/test.n3#> .@prefix db: <> .@prefix vocab: <vocab/> .@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .@prefix d2rq:

<http://www.wiwiss.fu-berlin.de/suhl/bizer/D2RQ/0.1#> .map:database a d2rq:Database;

d2rq:jdbcDriver "com.mysql.jdbc.Driver";d2rq:jdbcDSN "jdbc:mysql://localhost/test";d2rq:username "root";d2rq:password "deekvish123";.

# Table departmentmap:department a d2rq:ClassMap;

d2rq:dataStorage map:database;d2rq:uriPattern "department/@@department.deptid@@";d2rq:class vocab:department;.

map:department__label a d2rq:PropertyBridge;d2rq:belongsToClassMap map:department;d2rq:property rdfs:label;d2rq:pattern "department #@@department.deptid@@";.

map:department_deptid a d2rq:PropertyBridge;d2rq:belongsToClassMap map:department;d2rq:property vocab:department_deptid;d2rq:column "department.deptid";d2rq:datatype xsd:int;.

map:department_dname a d2rq:PropertyBridge;d2rq:belongsToClassMap map:department;d2rq:property vocab:department_dname;d2rq:column "department.dname";.

# Table employee

map:employee a d2rq:ClassMap;

d2rq:dataStorage map:database;

d2rq:uriPattern "employee/@@employee.empid@@";

d2rq:class vocab:employee;

.

map:employee__label a d2rq:PropertyBridge;


d2rq:property rdfs:label;

d2rq:pattern "employee #@@employee.empid@@";

.

map:employee_empid a d2rq:PropertyBridge;


d2rq:property vocab:employee_empid;

d2rq:column "employee.empid";

d2rq:datatype xsd:int;

.

map:employee_ename a d2rq:PropertyBridge;


d2rq:property vocab:employee_ename;

d2rq:column "employee.ename";

.

map:employee_deptid a d2rq:PropertyBridge;


d2rq:property vocab:employee_deptid;

d2rq:refersToClassMap map:department;

d2rq:join "employee.deptid = department.deptid";.

D2RQ Command Line Tools (Cont’d)Dumping the Database to an RDF File: “dump-rdf” script

Used to dump the contents of the entire database into a single RDF file

Usage: dump-rdf -u username [-p password] -d driverclass -j jdbcURL [output parameters]

Example – With Mapping File: dump-rdf –m test.n3 –o test.rdfWithout Mapping File: dump-rdf -u root -p deekvish123 -d

com.mysql.jdbc.Driver -j jdbc:mysql://localhost/test –o test.rdf

Sample Dumped RDF File<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:map="file:///C:/SUNITHA/D2RQ/D2RSER4/test.n3#" xmlns:vocab="file:///C:/SUNITHA/D2RQ/D2RSER4/vocab/" xmlns:xsd="http://www.w3.org/2001/XMLSchema#" xmlns:db="file:///C:/SUNITHA/D2RQ/D2RSER4/test2.rdf" xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#" > <rdf:Description rdf:about="#department/20"> <vocab:department_dname>Accounts</vocab:department_dname> <vocab:department_deptid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">20</vocab:department_deptid> <rdfs:label>department #20</rdfs:label> <rdf:type rdf:resource="vocab/department"/> </rdf:Description> <rdf:Description rdf:about="#employee/45678"> <vocab:employee_deptid rdf:resource="#department/30"/> <vocab:employee_ename>HRGuy</vocab:employee_ename> <vocab:employee_empid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">45678</vocab:employee_empid> <rdfs:label>employee #45678</rdfs:label> <rdf:type rdf:resource="vocab/employee"/> </rdf:Description> <rdf:Description rdf:about="#employee/12345"> <vocab:employee_deptid rdf:resource="#department/10"/> <vocab:employee_ename>Nisha</vocab:employee_ename> <vocab:employee_empid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">12345</vocab:employee_empid> <rdfs:label>employee #12345</rdfs:label> <rdf:type rdf:resource="vocab/employee"/> </rdf:Description>

Sample Dumped RDF File (Cont’d)<rdf:Description rdf:about="#department/30"> <vocab:department_dname>HR</vocab:department_dname> <vocab:department_deptid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">30</vocab:department_deptid> <rdfs:label>department #30</rdfs:label> <rdf:type rdf:resource="vocab/department"/> </rdf:Description> <rdf:Description rdf:about="#employee/34567"> <vocab:employee_deptid rdf:resource="#department/20"/> <vocab:employee_ename>AccountantGuy</vocab:employee_ename> <vocab:employee_empid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">34567</vocab:employee_empid> <rdfs:label>employee #34567</rdfs:label> <rdf:type rdf:resource="vocab/employee"/> </rdf:Description> <rdf:Description rdf:about="#employee/23456"> <vocab:employee_deptid rdf:resource="#department/10"/> <vocab:employee_ename>Meera</vocab:employee_ename> <vocab:employee_empid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">23456</vocab:employee_empid> <rdfs:label>employee #23456</rdfs:label> <rdf:type rdf:resource="vocab/employee"/> </rdf:Description> <rdf:Description rdf:about="#department/10"> <vocab:department_dname>Research</vocab:department_dname> <vocab:department_deptid

rdf:datatype="http://www.w3.org/2001/XMLSchema#int">10</vocab:department_deptid> <rdfs:label>department #10</rdfs:label> <rdf:type rdf:resource="vocab/department"/> </rdf:Description></rdf:RDF>

D2RQ ServerTool for publishing the content of relational databases

on the Semantic WebHas a Linked Data Interface and allows RDF data to

be browsed and searchedSPARQL interface enables applications to search and

query the database using the SPARQL Query Language

Traditional HTML interface offers access to the familiar Web browsers

Running the D2RQ ServerGenerate the mapping file for the database schemaStart the server

Command: d2r-server mapping.n3

Example: d2r-server test.n3

Test the serverOpen http://localhost:2020/ in a Web browser

Screenshot of Example D2RQ Server

More Screenshots

Background Server Activity

AgendaD2RQ BasicsR2D (RDF-to-Database) Research

MotivationR2D System ArchitectureR2D Modules

RDFMapFileGeneratorDBSchemaGeneratorSQL-to-SPARQL Translation

Experimental ResultsConclusions & Future Work

21

R2D – Research Motivation & Objectives

Current Trend: Semantic Web initiative for automated storage, exchange, and usage of machine-readable information.

Effects of current trend: Resource Description Framework and RDF Graph data model to realize the Semantic Web Initiative.

Challenges due to current trend: Demand for RDF data modeling and visualization tools.

Addressing these challenges:Readily available mature relational data modeling and

visualization tools are leveraged for RDF data models by reusing the same.

We propose R2D, a JDBC wrapper around RDF stores that bridges the gap between RDF and RDBMS concepts and presents a relational view of the RDF store to the modeling and visualization tools.

22

R2D System ArchitectureR2D’s Modules1.RDFMapFileGenerator:

Automatic RDF-to-Relational Schema mapping file generator utility.

2.DBSchemaGenerator: Parser that takes the above map file as input and generates a domain-specific, normalized, virtual relational schema for the corresponding RDF store.

3.SQL-to-SPARQL Translation: Utility that takes an SQL statement as input, parses & converts it to a corresponding SPARQL statement, executes the same, & returns the results in a tabular format.

23Fig. 1: R2D’s Architecture

Introduction –RDF 101Resource Description Framework (RDF) is a

language for:Representing information about resources on the

WWWPresenting metadata about web resources (such as

title and author of a web page)RDF is computer readable and understandableRDF is W3C’s answer to realization of the

Semantic Web – a framework that allows data to be shared and reused across applications.Achieved through the reuse of appropriate

concepts, thereby avoiding concept matching issues across rival formalizations

Introduction –RDF 101Every RDF statement

is a triple of the form <subject, predicate,

object>

RDF model is a graph – the object of one statement can be the subject of another

Sample RDF Graph

R2D In Action

26

RDFMapFileGeneratorFirst component in the R2D Transformation FrameworkGenerates a map file containing the correlations between

an RDF store’s meta-data and its relational equivalentsMapping constructs and map file generation process:

R2d:TableMap: Construct used to map rdfs:class objects to an equivalent relational table

R2d:BelongsToTableMap: Construct that connects property column bridge to the r2d:TableMap corresponding to the “subject” of the property node

R2d:Predicate: Construct that keeps track of the fully qualified predicate name of the property comprising the r2d:ColumnBridge.

R2d:ColumnBridge: Construct that maps single-valued simple properties to relational database columns

R2d:MultiValuedColumnBridge: Construct that maps those predicates that have multiple object values for the same subject

R2d:RefersToTableMap: Construct that establishes a foreign key relationship between the source r2d:TableMap and the parent r2d:TableMap corresponding to the resource object of a triple

EmpURI/EmpA

Link to Project1

Works On

Link to Project2

Link to ProjectN

Works On

Works On

<Name>

NickName

R2d:TableMap

R2d:KeyField: Construct that attaches a dummy primary key field to the r2d:TableMap associated with a resource.

R2d:KeyField (Value)

R2d:ColumnBridge

R2d:MultiValuedColumnBridge

R2d:BelongsToTableMap

R2d:Predicate

R2D:RefersToTableMap

R2D:TableMap corresponding to

“Project” Resources

27

RDFMapFileGeneratorR2d:SimpleLiteralBlankNode (SLBN): Construct used to relate blank nodes with distinct simple literal objects to relational database columns

R2d:SimpleLiteralBlankNode

EmpURI/EmpA

<Street>

<City>

CityStree

t

Address

State

<State>

R2d:ComplexLiteralBlankNode (CLBN): Construct used to relate blank nodes containing repeating predicates (with simple literal objects)to relational database columns

EmpURI/EmpA

<WorkNo>

<CellNo>

Phone

CellCell Work

<CellNo>

R2d:ComplexLiteralBlankNode

R2d:MultiValuedPredicate: Construct used when there are multiple predicate names that refer to the same overall object type

R2d:BelongsToBlankNode: Construct used relate the property column bridges to their parent blank node


EmpURI/EmpA

<Street>

<City>

CityStree

t

Address

State

<State>

EmpURI/EmpA

<WorkNo>

<CellNo>

<CellNo>

Phone

CellCell Work

R2d:ComplexLiteralBlankNode

R2d:MultiValuedPredicate

R2d:BelongsToBlankNode

EmpURI/EmpA

Home Address

<State><City

>

<Street>

State

CityStreet

Work Address

<State><City

>

<Street>

State

CityStreet

R2d:MultiValuedSimpleLiteral BlankNode (MVSLBN): Construct used to relate duplicate SLBNs to relational database columns

R2d:MultiValuedComplexLiteral BlankNode (MVCLBN): Construct used to relate duplicate CLBNs to relational database columns

EmpURI/EmpA

Present Phone

Numbers

<Work><Work

>

<Cell>

Work

WorkCell

Past Phone

Numbers

<Work><Cell

>

<Cell>

Work

CellCell

R2d:SimpleResourceBlankNode (SRBN): Construct used to map blank nodes that have multiple predicates leading to resource objects belonging to the same object class

EmpURI/EmpA

Projects

Link to

Project1 Link to

Project2

Link to Project

3

Works On

Works On

Works On

R2d:ComplexResourceBlankNode (CRBN): Construct used to map blank nodes leading to objects belonging to difference object classes

EmpURI/EmpA

Other Activitie

s

Link to Trainin

g1

Link to

Course1

Training

Teaching

R2d:MultiValuedSimple LiteralBlankNode

R2d:MultiValuedPredicateR2d:MultiValuedPredicate

R2d:MultiValuedCom-plexLiteralBlankNode

R2d:SimpleResourceBlankNode

R2d:ComplexResourceBlankNode

R2d:MultiValuedPredicate

RDFMapFileGenerator – Map File Excerpts

map:Employee a r2d:TableMap;r2d:keyField Employee_PK;

map:Name a r2d:SimpleLiteralBlankNode;r2d:belongsToTableMap map:Employee;r2d:predicate <http://employee/Name>;

map:Name_First a r2d:ColumnBridge;r2d:belongsToBlankNode map:Name;r2d:datatype xsd:String;r2d:predicate <http://employee/Name/First>;

map:Employee_Nickname a r2d:ColumnBridge;r2d:belongsToTableMap map:Employee;r2d:datatype xsd:String;r2d:predicate <http://employee/Nickname>;

map:Employee_Department a r2d:ColumnBridge;r2d:belongsToTableMap map:Employee;r2d:refersToTableMap map:Department;r2d:datatype xsd:String;r2d:predicate <http://employee/Department>;

map:Phone a r2d:ComplexLiteralBlankNode;r2d:belongsToTableMap map:Employee;r2d:predicate <http://employee/Phone>;

map:Phone_Value a r2d:MultiValuedColumnBridge;r2d:belongsToBlankNode map:Phone;r2d:datatype xsd:String;r2d:MultiValuedPredicate Phone_Type;

map:Phone_Type a r2d:MultiValuedPredicate;r2d:predicate <http://employee/Phone/Cell>;r2d:predicate <http://employee/Phone/Home>;

map:Projects a r2d:SimpleResourceBlankNode;r2d:belongsToTableMap map:Employee;r2d:predicate <http://employee/Projects>;

map:Projects_WorksOn a r2d:MultiValuedColumnBridge;r2d:belongsToBlankNode map:Projects;r2d:refersToTableMap map:Project;r2d:datatype xsd:String;r2d:predicate <http://employee/Project>;

29

EmpURI/EmpA

<First>

<Middle>

Middle

First

Name

Last

<Last>

<NickName>

NickName Departmen

t

Link to Departme

nt

EmpURI/EmpA

<CellNo>

<CellNo>

CellCell

Phone

Work

<WorkNo>

Projects

WorksOn

WorksOn

WorksOn

Link to

Project1

Link to Project

2

Link to Project

3

R2D In Action

30

DBSchemaGeneratorSecond component in the R2D Transformation FrameworkUsing the map file as input, generates the actual virtual

normalized relational schema for the RDF store A new table is created in the equivalent relational schema

in the following scenarios:

(a) When a distinct resource class is encountered (i.e. when an r2d:TableMap construct is encountered in the Map File)

(b) When duplicate predicates with literal objects are encountered (i.e. when an r2d:MultiValuedColumnBridge predicate is encountered)

(d) When a blank node (or nodes) is encountered that has multiple predicates (some, but not all, distinct), each leading to literal values from the same object class (i.e. when an r2d:ComplexLiteralBlankNode (CLBN) or r2d:MultiValuedCLBN is encountered)

(e) When N:M relationships between the subject and object resources are encountered (i.e. when r2d:MVCBs or SRBNs or CRBNs with appropriate mutually referencing r2d:RefersToTableMap constructs are encountered in both the subject as well as the object resources)

EmpURI/EmpA

<WorkNo>

<CellNo>

<CellNo>

Phone

CellCell Wor

k

R2d:ComplexLiteralBlankNode 31

R2d:MultiValuedColumnBridge

EmpURI/EmpA

<Dependent>

Dependent

<Dependent>

<Dependent>

Dependent

Dependent

SRBN referencing Project

SRBN referencing Employee

(c) When multiple similar blank nodes with distinct simple literal predicates are encountered (i.e. when an r2d:MultiValuedSimpleLiteralBlankNodes is encountered)

R2d:TableMap

R2d:MultiValuedSimpleLiteralBlankNode

DBSchemaGeneratorEmpURI/

EmpA

<Name>

Name

R2d:TableMap

R2d:ColumnBridge

Column

All simple properties, i.e., simple r2d:ColumnBridges, become columns in the r2d:TableMap corresponding to the subject of the property

Properties belonging to r2d:SimpleLiteralBlankNodes become columns in the r2d:TableMap corresponding to the subject of the blank node

32

EmpURI/EmpA

<Street>

<City>

CityStree

t

Address

State

<State>


R2d:TableMap

Columns

Sample RDF Graph with Reification & its Relational Equivalent

33

R2D In Action

34

SQL2SPARQL TranslationLast stage in the R2D Transformation FrameworkTranslates SQL statements issued against the

virtual relational schema into equivalent SPARQL queries to be executed against the actual RDF store

Obtained results are returned to the relational tool in tabular format

Sample QuerySELECT Name_First, Name_last, Phone_Value, department_name

FROMemployee, employee_Phone, department WHERE

employee.employee_PK= employee_Phone.employee_PK and employee_Phone.Phone_Type =<http://Phone/Cell> and employee.department_id =department.department_id AND (name_First LIKE ‘ABC%’ ORemployee_pk = <http://empl/123>);

SQL2SPARQL Translation

SELECT Name_First, Name_last, Phone_Value, department_name FROM employee, employee_Phone, department WHERE employee.employee_PK = employee_Phone.employee_PK and employee_Phone.Phone_Type = <http://Phone/Cell> and employee.department_id = department.department_id AND (name_First LIKE ‘ABC%’ OR employee_pk = <http://empl/123>); SPARQL SELECT list – One variable for every field in the SQL SELECT listSparqlSELECT = SELECT ?name_First ?name_Last, ?Phone_Value ?department_name

SPARQL WHERE clause – A clause of the form <s, p, o> for every variable in the SPARQL SELECT list

SparqlWHERE = WHERE {?subject0 <http://empl/Name> ?employee_name .?employee_Name <http://Name/First> ?name_First .?employee_Name <http://Name/Last> ? name_Last .?subject0 <http://empl/deptId> ?employee_department_id .?subject1 <http://dept/dept_name> ?department_name .?subject0 http://empl/Phone ?employee_Phone .?employee_Phone ?Phone_Type ?Phone_Value .

SPARQL FILTER clause – A clause added for each SQL WHERE clauseSparqlFILTER = FILTER ( ?Phone_Type = <http://Phone/Cell> &&employee_department_id = subject1 && (regex(?name_First, “^ABC”)|| ?subject0 = http://empl/123) }

SQL2SPARQL TranslationProcessing of fields corresponding to blank nodes

If field belongs to an r2d:SimpleLiteralBlankNode, the following clauses are added

{?subject<tableIndex> <BlankNode.Predicate> ?<BlankNode.Name> . ?<BlankNode.Name> <Field.Predicate> ?<Field.Name> . }

Example: Clauses resulting from processing of the “Name_First” and “Name_Last” field

?subject0 <http://empl/Name> ?employee_name .?employee_Name <http://Name/First> ?name_First .?employee_Name <http://Name/Last> ? name_Last .

EmpURI/EmpA

<First>

<Middle>

Middle

First

Name

Last

<Last>


If field belongs to an r2d:ComplexLiteralBlankNode or other blank nodes consisting of r2d:MultiValuedPredicates, the following clauses are added to the SPARQL WHERE and FILTER clauses?subject<tableIndex> ?<MVPColumn.Name> ?<NonMVPColumn.Name>?<BlankNode.Name> ?<MVPColumn.Name> ?<NonMVPColumn.Name>

FILTER {?<MVPColumn.Name> = <PredicateName>}Example: Clauses resulting from processing of the “Phone_Value” field (corresponding to the “Cell” and “Work” predicates) belonging to the “Phone” SLBN

?subject0 http://empl/Phone ?employee_Phone .?employee_Phone ?Phone_Type ?Phone_Value .

FILTER {?Phone_Type = <http://Phone/Cell>}

EmpURI/EmpA

<CellNo>

<CellNo>

CellCell

Phone

Work

<WorkNo>


Transformed Equivalent SPARQL Query

SELECT ?name_First ?name_Last, ?Phone_Value ?department_name WHERE {?subject0 <http://empl/Name> ?employee_name .?employee_Name <http://Name/First> ?name_First .?employee_Name <http://Name/Last> ? name_Last .?subject0 <http://empl/deptId> ?employee_department_id .?subject1 <http://dept/dept_name> ?department_name . ?subject0 http://empl/Phone ?employee_Phone .?employee_Phone ?Phone_Type ?Phone_Value . FILTER ( ?Phone_Type = <http://Phone/Cell> &&employee_department_id = subject1 && (regex(?name_First, “^ABC”) || ?subject0 = http://empl/123) }

Original SQL QuerySELECT Name_First, Name_last, Phone_Value, department_name FROM

employee, employee_Phone, department WHERE employee.employee_PK = employee_Phone.employee_PK and employee_Phone.Phone_Type = <http://Phone/Cell> and employee.department_id = department.department_id AND (name_First LIKE ‘ABC%’ OR employee_pk = <http://empl/123>);

R2D In Action

40

Experimental Results RDF Schema used in the

experiments

41

Map File Generation Times

42

Experimental Results Sample Query through Datavision

Query Processing Times

44

ConclusionsA JDBC interface called R2D that bridges the gap

between RDF data stores and relational databases has been introduced.

Screenshots from a relational visualization tool called Datavision were presented as evidence of the feasibility of our research and the performance of queries against databases of various sizefss are also presented.

Future Work Improving the normalization process for mixed blank

nodesSupport for translation of a richer selection of SQL

statements including nested and correlated sub-queries

45

Related Publications1) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “Relationalizing RDF

Stores for Tools Reusability”, In 18th International World Wide Web Conference, 2009, pp. 1059-1060. (Nominated for Best Poster Award)

2) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “R2D: Extracting Relational Structure from RDF Stores”, Accepted for publication in Proceedings of the International Conference on Web Intelligence, September 16-18, 2009.

3) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “A Relational Wrapper for RDF Reification”, Accepted for publication in Proceedings of the International Conference on Trust Management, June 16-19, 2009.

4) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “R2D: A Bridge between the Semantic Web and Relational Visualization Tools”, Accepted for publication in International Conference on Semantic Computing, September 14-16, 2009.

5) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “A Framework for the Relational Transformation of RDF Data”, Submitted to the International Journal on Semantic Computing (Invited Paper).

6) S.Ramanujam, A.Gupta, L.Khan, S.Seida, and B.Thuraisingham, “Relationalization of Provenance Data in Complex RDF Reification Nodes”, Submitted to the Electronic Commerce Research Journal - special issue on Trust and Privacy Aspects of Electronic Commerce (Invited Paper).

Thank You

47

1 sunitha ramanujam 1, anubha gupta 1, latifur khan 1, steven seida 2, bhavani thuraisingham 1 1 the...

Documents