Semantika Introduction

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A brief introduction about Semantika and its core solution in providing query service.

Project website: http://obidea.github.io/semantika-api/

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Semantika Introduction

  1. 1. Semantika Relational to RDF Mapping and Transparent Data Access for SPARQL over SQL Databases
  2. 2. Facts about Semantika • True transparent data access. • Non-intrusive and utilizes fully over existing database. • Query language aligned with SPARQL. • High priority on performance.
  3. 3. What is Semantika? • Semantika is a robust, high-performance RDB-to-RDF connector and data access add-on API for Java and SQL. Semantika provides interface for building semantic query machine over your existing database. The solution is non-intrusive and risk-free for your valuable data.
  4. 4. What is Semantika? • Semantika framework is based on Ontology-based Database Access (OBDA) paradigm that combines the best of semantic discipline and relational database technology. • It offers API support and high processing performance.
  5. 5. Semantika Core Components • RDB/RDF Mapping, • Common Query Expression.
  6. 6. RDB/RDF Mapping • Mapping domain entities and relational data, • Solution for the infamous object-relation impedance mismatch, • Finally application can focus on domain specification.
  7. 7. Common Query Expression • Using one query to retrieve sets of data without knowing what relational database is the target. • The query articulation is no longer tight on a specific data schema; instead it is bundled with terminology of your own through SPARQL language.
  8. 8. Why use Semantika? • Simple to implement, • Isn’t intrusive, no migration is required. • Instant added-value to your existing data query system, • Query mechanism closely resembles SQL so learning curve is low, • Useful for data publishing to public.
  9. 9. What makes up a Semantika application? • Domain Ontology, • RDB/RDF Mapping Specification, • Semantika Configuration
  10. 10. Domain Ontology • A formal specification of the domain application. SubClassOf(TechnicalStaff, Employee) SubClassOf(OperationalStaff, Employee) SubClassOf(Manager, Employee) DataPropertyDomain(firstName, Employee) DataPropertyDomain(lastName, Employee) DataPropertyDomain(hireDate, Employee) ObjectPropertyDomain(memberOf, Employee) ObjectPropertyRange(memberOf, Department)
  11. 11. RDB/RDF Mapping • A formal specification about the relationship between data in database and entities in ontology. <mapping tml:id="Mapping1"> <logical-table rr:tableName="EMPLOYEES"/> <subject-map rr:template="Employee(EMP_NO)"/> <predicate-object-map rr:predicate="firstName" rr:column="FIRST_NAME"/> <predicate-object-map rr:predicate="lastName" rr:column="LAST_NAME"/> <predicate-object-map rr:predicate="hireDate" rr:column="HIRE_DATE"/> </mapping> Ontology entities Database columns
  12. 12. Semantika Configuration • A collection of database settings and file resources. <semantika-configuration> <application-factory name="empapp"> <data-source> <property name="connection.url">jdbc:h2:tcp://localhost/empdb</property> <property name="connection.driver_class">org.h2.Driver</property> <property name="connection.username">sa</property> <property name="connection.password"></property> </data-source> <ontology-source resource="model/empdb.owl" /> <mapping-source resource="model/empdb.tml.xml" /> </application-factory> </semantika-configuration>
  13. 13. Semantika Classes • ApplicationFactory - Consumer of Semantika configuration file. System initialization happens here. Creates ApplicationManager. • ApplicationManager - One instance per app. Provides query engine for query answering interface.
  14. 14. Semantika Classes • SparqlQueryEngine - Default query engine that takes input SPARQL and returns QueryResult. • RdfMaterializerEngine - RDB-to-RDF export tool. Useful for open data publishing.
  15. 15. Semantika Use Scenario IT-experts end-user model query communicate software agent ontology mappings Semantika Core Framework SQL Databases (reproduced from Optique 1.0: Semantic Access to Big Data presentation)
  16. 16. Things to Take In • Semantika is a robust, non-intrusive platform for your semantic search need. • Semantika offers you a new and intelligent way for querying relational data through semantic search. • Semantika helps to extract your domain information into standard documents that is useful for knowledge sharing.
  17. 17. Visit our Site: http://obidea.github.io/semantika-api/ Project Extras: Command-line Tool: https://github.com/obidea/semantika-cli SPARQL endpoint with Sesame: https://github.com/obidea/semantika-sesame

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