OpenLink Virtuoso - SQL & RDF
RDF Views of SQL Data
(Exposing SQL Data as RDF)
Orri Erling
Program Manager - OpenLink Virtuoso
mailto:oerling@openlinksw.com

Virtuoso Universal Server
Native SQL & XML DBMS
Federated / Hybrid Data Server (Virtual Database Engine)
Web Services Platform
SQL to RDF Mapping
Native RDF Quad Store (with SPARQL support)
In-built RDF Middleware (“Sponger”)
RDF Linked Data Deployment Platform

Situation Analysis
Data Drives Everything
Data Heterogeneity is a fact of life
There is no Information without Data
The Era of Information Overload is Neigh
Information Processing drives Corporate & Individual Agility

What We Hope
Write The
Final Chapter of the Information Integration Saga!

Yes, if...
SPARQL to Match SQL for BI Queries
Tools and Training for the Information Architect
Successful Migration of Domain Specific XML Vocabularies to RDF

An Ideal Solution

Virtuoso’s
RDF Views of SQL Data
Functionality

What are RDF Views?
Expose pre-existing relational data as virtual RDF graphs
Available for querying through SPARQL or SPASQL (SPARQL embedded in SQL)
No physical regeneration of relational data

Virtuoso RDF Views Implementation
Quad Patterns Translate Relational Data to G, S, P, O
Map Local or Heterogeneous Remote Data To RDF
Map XML/Text/Web Services to RDF via Table Valued Functions
Sophisticated Query Transformations and Optimization

Virtuoso SPARQL and SQL Extensions
Aggregates, Grouping, Full Text for SPARQL
SQL "Breakup" for Mapping Wide Rows to n-Triples
Freely Intermingle SQL and SPARQL

Northwind Demo Database
Tables include:

Northwind Demo Database:
RDF View Definition Extract
prefix northwind: <http://www.openlinksw.com/schemas/northwind#>
…
create iri class northwind:Customer
<http://^{URIQADefaultHost}^/Northwind/Customer/%U#this> (in customer_id varchar not null)
…
alter quad storage virtrdf:DefaultQuadStorage
…
from Demo.demo.Customers as customers
from Demo.demo.Orders as orders … {

Northwind Demo Database:
RDF View Definition Extract
prefix northwind: <http://www.openlinksw.com/schemas/northwind#>
…
create iri class northwind:Order
<http://^{URIQADefaultHost}^/Northwind/Order/%d#this> (in order_id integer not null) .
…
alter quad storage virtrdf:DefaultQuadStorage
…
from Demo.demo.Customers as customers
from Demo.demo.Orders as orders … {

Northwind Demo Database:
Customer Table to RDF Entity Mapping

Facilitate Information at Your Finger Tips
Provide a Conceptual View of Logical Data
Make the Conceptual Views concrete focal points of Data Access
Identify Data Entities using URIs (Data Links) e.g http://demo.openlinksw.com/Northwind/Customer/ALFKI#this
Identify Associations / Relationships with other Entities using URIs e.g http://www.openlinksw.com/schemas/northwind#has_order

SQL-RDF Mapping Experiences
Mapping is Non-Trivial
Problems Start When Many Tables Map to the Same Thing
Choice of URI Scheme Can Greatly Affect Optimization Possibilities

What We Need
Interop of Necessary SPARQL Extensions
Visual Tools for SQL-RDF Mapping
SQL-RDF Mapping Syntax Standardization
Community Consensus on RDF Vocabularies

It is NOT about RDF vs. XML vs. SQL
Web Services are for Transactions and App. Integration
RDF is for Disparate Data Meshing, Discovery, and Drill Down/Analysis
SQL is Forever

SQL-RDF Integration Value
Enterprise: Alleviation of heterogeneous data integration challenges
Public: A Whole Economy of Discoverable Linked Data and Data Mesh-ups
Now: Full Text For All - Next: Analysis For All

OpenLink Futures
Commercial Deployment of SQL to RDF Mapping
Towards Web-scale with Clustered RDBMS/Triple Store
OpenLink Data Spaces (ODS) for Bootstrapping SemWeb Presence

Additional Information
http://virtuoso.openlinksw.com (general site)
http://virtuoso.openlinksw.com/wiki/main/ (Open Source Edition Site)
http://virtuoso.openlinksw.com/Whitepapers/index.htm (OpenLink Data Spaces)

Thank You!