- Sunitha Ramanujam, Vaibhav Khadilkar, Latifur Khan, Steven Seida, - - PowerPoint PPT Presentation
- Sunitha Ramanujam, Vaibhav Khadilkar, Latifur Khan, Steven Seida, Murat Kantarcioglu, Bhavani Thuraisingham Agenda Research Motivation Current Work in the Arena Our Approach D2RQ Basics The D2RQ++ Approach Algorithms
D2RQ Basics The D2RQ++ Approach Algorithms comprising D2RQ++
Experimental Results
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 applications
to access content of huge, live, legacy databases
Addressing these challenges:
legacy database schemata and RDF-S/OWL ontologies.
enabling inserts/updates/deletes to be propagated back to legacy databases thus making the translation process bidirectional.
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Ontology-based write access to relational data via SPARQL/Update.
Consists Of....
R3M – Update-aware RDBMS to RDF mapping language
Algorithms – Translate SPARQL/Update to SQL DML
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TableMap Listing
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AttributeMap Listing
LinkTableMap Listing
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INSERT Data
Wrapper around D2RQ that enables inserts/updates/deletes
Algorithms to translate RDF update triples into equivalent
Extensions to support translation of blank node structures
Preservation of the Open-World Assumption by
Semantic Web Technologies are maturing Growing need for RDF applications to access legacy
Query a non-RDF database using SPARQL Access information in a non-RDF database using the Jena
Access the contents of a non-RDF database as Linked
Tool for publishing content of relational databases on the
Consists of
D2RQ Mapping Language D2RQ Engine D2RQ Server
Triples that do not have an equivalent entity/attribute
Duplicate triples that would otherwise result in
Subsequent querying of corresponding attribute returns a
union of both values from the two data stores.
d2rq:SimpleLiteralBlankNode Property Bridge(SLBNPB): Construct used to relate blank nodes that have only literal objects, each with a unique predicate
EmpURI/EmpA <Street> <City>
City Street Address State
<State>
d2rq:SLBNPB
d2rq:ComplexLiteralBlankNode PropertyBridge(CLBNPB): Construct used to relate blank nodes containing repeating predicates (with simple literal objects) to relational database columns
EmpURI/EmpA <WorkNo> <CellNo>
Phone Cell Cell Work
<CellNo>
d2rq:CLBNPB
d2rq:ResourceBlankNode (RBNPB): Construct used to map blank nodes that have multiple predicates (that may
resource objects
EmpURI/EmpA
Projects
Link to Project1 Link to Project2 Link to Project3
Works On Works On Works On
EmpURI/EmpA
Other Activities
Link to Training1 Link to Course1
Training Teaching
d2rq:RBNPB
d2rq:BelongsToBlankNode: Construct used to relate a relational attribute to the parent blank node
d2rq:SLBNPB
EmpURI/EmpA <Street> <City>
City Street Address State
<State>
d2rq:CLBNPB
EmpURI/EmpA <WorkNo> <CellNo>
Phone Cell Cell Work
<CellNo>
d2rq:BelongsToBlankNode
map:employee_address a d2rqrw:SimpleLiteralBlankNodePropertyBridge; d2rq:belongsToClassMap map:employee; d2rq:property vocab:employee_address; d2rq:propertyDefinitionLabel "employee address"; d2rq:pattern "@@employee.address_street@@/ @@employee.address_city@@/ @@employee.address_state@@"; . map:employee_address_street a d2rq:PropertyBridge; d2rqrw:belongsToBlankNode map:employee_address; d2rq:belongsToClassMap map:employee; d2rq:property vocab:employee_address_street; d2rq:propertyDefinitionLabel "employee address_street"; d2rq:column "employee.address_street";
EmpURI/EmpA <Street> <City>
City Street Address State
<State>
Sample Map File Entry for an SLBNPB
Triples violating referential integrity constraints initially
Native RDF Store triples periodically checked to verify
If yes, then triple transferred to relational database and
deleted from native RDF store
EmpURI/EmpA <Street> <City>
City Street Address State
<State>
Initial Data in MySQL Relational Database Schema
D2R++Server Interface for adding a second name for an existing EmpID
model.add( model.createResource( "file:///home/vaibhav/employee.n3#empl
model.createProperty( "http://localhost:2020/vocab/resource/em ployee_empName" ), model.asRDFNode( Node.createLiteral( “Doe" ) ) );
Data in MySQL Relational Database Schema and native RDF Store after adding a second name for an existing EmpID
model.add( model.createResource( "file:///home/vaibhav/emplo yee.n3#employee/1" ), model.createProperty( "http://localhost:2020/vocab /resource/employee_empNa me" ), model.asRDFNode( Node.createLiteral( “Doe" ) ) );
D2R++Server User Interface after adding a second name for an existing EmpID
Data in MySQL Relational Database Schema and native RDF Store after adding a new triple with a brand new EmpID
model.add( model.createResource( "file:///home/vaibhav/employ ee.n3#employee/2" ));
D2R++Server User Interface after removing the original and duplicate names for an existing EmpID
Data in MySQL Relational Database Schema and native RDF Store after removing the original and duplicate names for an existing EmpID
Data in MySQL Relational Database Schema and native RDF Store after removing an existing EmpID
model.remove( model.createResource( "file:///home/vaibhav/emplo yee.n3#employee/2" ), model.createProperty( "http://localhost:2020/vocab /resource/employee_empid" ), model.asRDFNode( Node.createLiteral( “2", null, XSDDatatype.XSDint ) ) );
A bi-directional RDBMS-to-RDF translation mechanism,
Screenshots of underlying relational database schema data
Future Work
Extending the flush algorithm to cover additional scenarios Adding support for the concept of RDF Reification
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