1. © 2008 IBM Corporation Supporting Ontology-based Dynamic Property and Classification in WebSphere Metadata Server Shengping Liu 1, Yang Yang 1, Guotong Xie 1, Chen Wang 1, Feng Cao 1, Cassio Dos Santos 2, Bob Schloss 3, Yue Pan 1, Kevin Shank 2, John Colgrave 2 1 IBM China Research Lab 2 IBM Software Group 3 IBM Watson Research Center

2. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Outline  Problem and solution  System in details –System architecture –Dynamic property and classification scheme –XMQL++ query language and processing  Use study

3. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Enterprise metadata management  There are so many kinds of metadata in enterprise –Technical metadata: relational schemas, XML schemas, schema mappings, UML models and messages, Web service descriptions, etc. –Business metadata: business concepts, business rules and business process, etc.  Metadata management has become the foundation of Data warehousing, Enterprise Information Integration and Service-Oriented Architecture (SOA)  Enterprise-wide metadata management –Not tool-specific or application-specific –Metadata are shared and integrated across multiple applications or even third party tools in enterprise

4. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Challenges of enterprise-wide metadata management  Handle evolving business requirements –It is impossible to design a unified meta-model for all kinds of metadata with all possible attributes and relationships at design stage –There is a requirement to dynamically add properties (attributes and relationships) for classes in the registered metamodel  Organize large volumes of metadata in different applications, for users from different business units, by metadata classification –There is a requirement for flexible and semantic-rich classification scheme

5. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Solution: applying Semantic Web technologies  Why Semantic Web technologies –Flexibility of RDF data model: –Treat properties as first-class citizens and allow them to be attached to a class dynamically –OWL is an emerging standard to represent the classification schemes –Rich expressivity, formal semantics and reasoning capabilities  How to apply –Extend the IBM WebSphere Metadata Server (MDS) with –Ontology-based dynamic properties (attributes and relationships ) –Represented as datatype properties and object properties in OWL –Can be attached the existing classes in MDS –Ontology-based metadata classification –Classification schemes are represented as OWL ontologies –Using OWL reasoner for metadata classification

6. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Outline  Problem and solution  System in details –System Architecture –Dynamic Property and Classification Scheme –XMQL++ Query Language and Processing  Use study

7. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Brief introduction to MDS and SOR  WebSphere Metadata Server (MDS) –A unified metadata services infrastructure that's designed to ease metadata management, access, and sharing within a service-oriented architecture –Packaged as a part of IBM new product: IBM Information Server (IIS) –Provides metadata management services to products in the IIS platform –A Object-Relational Mapping system that transform CRUD API and object query to SQL statements  Semantic Object Repository (SOR) –A High performance OWL ontology repository built on relational databases –Inference on loading, query without reasoning –SPARQL is rewritten to SQL –Support reasoning on OWL DL sub-language: DLP

8. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation System architecture  Integrated query language –Extend XMQL to support dynamic properties and classification  Integrated modeling paradigm –Based on EMF (Eclipse Modeling Framework)  Integrated runtime repository –The ontology repository is tight-coupled with the MDS repository Loosely coupled or tight-coupled? API integration? Reasoning on existing model? Hybrid query language or one extended query language?

9. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Ontology-based dynamic property  Semantic of dynamic property is similar to EMF property –Multiple domain and range is forbidden for dynamic property –Multiplicity of a dynamic property is always 0..*  Dynamic attribute –Domain of a dynamic attribute is an EMF class –Range of a dynamic attribute can be: EChar, EInt, and EString,etc.  Dynamic relationship –Domain and range of a dynamic relationship are EMF classes  Semantic annotations can be added for the property –Symmetric, transitive, subPropertyOf

10. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation When metadata shared by different usage context  Business Analyst –I want to add the business function information for WSDL service at runtime  Service Administrator –I want to add the response time information for WSDL service at runtime –I want to add the service status information for WSDL service at runtime businessFunction - Domain: WSDLService - Range: EString responseTime - Domain: WSDLService - Range: EInt serviceStatus - Domain: WSDLService - Range: EString Deployed WSDL model

11. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Domain & Range of “businessFunction” Deployed meta-models Add dynamic attributes at runtime UI for adding dynamic attribute

12. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation New relationships can be defined at runtime  Service Administrator –There is a new relationship between Web Services should be modeled: dependsOn –This relationship is transitive –I don’t want to change the old metamodel and redeploy it dependsOn - Domain: WSDLService - Range: WSDLService - type: owl:TransitiveProperty  Add a dynamic relationship –Declare its domain and range –Add semantic annotation: Transitive

13. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Adding “dependsOn”. Semantic annotation can be applied on dynamic relationships Domain & Range of “dependsOn” UI for adding dynamic relationship

14. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Ontology-based Classification  Supported features –Classification schema is represented as OWL ontology –A classifier is represented as a named class –A classification hierarchy is represented as an ontology –Dynamic classifier can be created using OWL class expression –Users need to create initial classification links from metadata in MDS to classifiers in the classification scheme –The system will deduce all implicit classification information by OWL reasoning

15. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Better Organization: Metadata Classification  Business Analyst –I want to view the services through the Insurance Services Taxonomy  Service Administrator –I want to organize the services through the service life-cycle taxonomy –I want to classify the service according to its service status information Insurance Service Taxonomy Serivice Life-cycle Taxonomy

16. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation OWL Expressions Can Be Used to Defined Classifiers  Service Administrator –I want to classify the service according to its service status and Insurance Services Taxonomy Insurance Service Taxonomy Serivice Life-cycle Taxonomy intersectionOf ClaimMgmtInProduction Ontology reasoner can automatically make reasoning according to the definition ClaimMgmtInProduction = ClaimMgmt  Production

17. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation OWL Restrictions Can Be Used to Defined Classifiers  owl:someValuesFrom: one of the property values is classified to a classifer –ClaimDependentSvc: the services that depend on a service which is classified to ClaimMgmt ClaimDependentSvc ClaimDependentSvc = InsuranceServices  dependsOn.ClaimMgmt dependsOn - Domain: WSDLService - Range: WSDLService - type: owl:TransitiveProperty OnProperty someValuesFrom

18. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Classify metadata according to the Classification scheme Select objects to be classified Select classifiers that the metadata is classified to Classification information has been set MotorClmHandling : ClaimHandling MotorClmHandling : Production MotorPolicyValidation : PolicyDataValidation Instance:

19. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation XMQL++ Query Language  XMQL –A subset of Object Query Language (OQL), for querying OO data –The basic structure is also select-from-where –For example, select the employee’ name who located in the United States that work for the project named “NewHotel”.  Extension with dynamic properties –Dynamic properties can appear as normal EMF properties in XMQL path expressions  Extension with classification –Classification functions are provided to enable queries over classification information in XMQL –Object[] classifiedBy(URI); URI[] classifiers(pathExpression):

20. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Some Examples  Get all WSDL services which are classified as DataService select x from x in WSDLService where x in classifiedBy(“http://foo.org/category#DataService”)  Get all WSDL services which are dependant on “service1” select x from y in WSDLService, x in y  dependsOn where y.serviceName =“service1”  Get all data services which are dependant on “service1” select x from y in WSDLService, x in y  dependsOn where y.serviceName = “service1” and x in classifiedBy(“http://foo.org/category#DataService”)

21. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation XMQL++ Query Processing  TripleQueryHandler will translate XMQL query extensions into SPARQL queries to ontology repository  SOR query engine will rewrite the queries to SQL sub-queries  XMQL++ Translator will merge the fragments with merge these sub queries with the SQL query generated for XMQL query

22. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Outline  Problem and solution  System in details –System architecture –Dynamic property and classification scheme –XMQL++ query language and processing  Use study

23. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Use study on China Healthcare Solution  HL7 Common Terminology Service –A list of APIs to manage terminologies  CTS APIs are implemented by using XMQL++ query  CTS vocabulary model is divided into two parts: –Static part stored in MDS –Dynamic part stored in SOR  For SNOMED CT –Add an dynamic attribute: designationCategory

24. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Observations  Essential features for the acceptance –Model flexibility –Users/programmers can attach any attributes or relationships to classes in the registered model without redeployment of the model. –Reasoning support –Programmers need not write additional code to handle the complex reasoning problems, such as the transitive closure computing. –User-friendliness –Users/programmers can write similar APIs and use our modestly extended query language to handle on dynamic properties and classifications. –The underlying Semantic Web technologies are mostly transparent for them  Hybrid storage pattern for complex metadata –Horizontal tables for the part of metadata with no reasoning involved –Vertical triple tables for the part of metadata with reasoning support or dynamic properties  Can not leverage the full expressivity of SPARQL query

25. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Conclusion  We present a practical system to provides support : –Manage semantic-rich properties and classifiers in the IBM WebSphere Metadata Server (MDS) by integrating the ontology repository SOR.  The experience to be shared –To enable the smooth acceptance of Semantic Web technologies for commercial metadata product developers with existing products, the integrated system should consist of integrated modeling paradigm, query language and runtime repository.

26. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Thank You Merci Grazie Gracias Obrigado Danke Japanese English French Russian German Italian Spanish Brazilian Portuguese Arabic Traditional Chinese Simplified Chinese Hindi Tamil Thai Korean

27. Information and Knowledge, IBM China Research Lab © 2008 IBM Corporation Related work  Dynamic attribute –Every class has a list of pairs each with a name and appropriate value  Dynamic relationship –Using weaving models [Stefanov 2006], in which a link have multiple link ends that each holding a reference to a model element.  Hybrid query language for SQL+SPARQL –Using a SQL table function RDF_MATCH [Chong 2005]