![R2RML Example
Student
ID
(PK)
FirstName LastName
10 Venus Williams
11 Fernando Alonso
12 David Villa
7
<Estudiante/11>
<Estudiante>
Fernando Alonso
rdf:type
ex:fullName
<#TriplesMap1>
rr:logicalTable [ rr:tableName "Student" ];
rr:subjectMap [
rr:template "http://data.example.com/Estudiante/{ID}";
rr:class ex:Estudiante;
];
rr:predicateObjectMap [
rr:predicate ex:fullName;
rr:objectMap [ rr:template "{FirstName} {LastName}" ];
].](https://image.slidesharecdn.com/mirror-automaticr2rmlmappinggenerationfromrelationaldatabasesicwe2015-150709083506-lva1-app6891/85/Semantic-Web-Technologies-and-Applications-track-MIRROR-Automatic-R2RML-Mapping-Generation-from-Relational-Databases-Luciano-Frontino-De-Medeiros-Freddy-Priyatna-and-Oscar-Corcho-7-320.jpg)
(Semantic Web Technologies and Applications track) "MIRROR: Automatic R2RML Mapping Generation from Relational Databases" - Luciano Frontino De Medeiros, Freddy Priyatna and Oscar Corcho
- 1. MIRROR: Automatic R2RML Mapping Generation from Relational Databases Luciano Frontino de Medeiros Freddy Priyatna Oscar Corcho The 15th International Conference on Web Engineering June 25th, 2015 Rotterdam, the Netherlands
- 2. Outline 1. Background & Motivation 2. Patterns Extraction 3. Mappings Generation 4. Experimentation 5. Conclusion 2
- 3. RDB2RDF 3 ● Two worlds o Relational Database (RDB) for storing information rows, tables o Resource Description Framework (RDF) for sharing information triples, graphs ● RDB2RDF and W3C
- 4. Direct Mapping ● Table URIs o <ex.com/Student> ● Row nodes o <Student/ID=10> ● Row type triples o <Student/ID=10> <rdf:type> Student ● Literal triples o <Sport/ID=110> <Sport#Description> “Tennis”. ● Reference triples o <Student_Sport/ID_Student=10;ID_Sport=110> <Student_Sport#ref-ID_Student> <Student/ID=10> . 4 http://www.w3.org/TR/rdb-direct-mapping/
- 5. Direct Mapping Example Student ID (PK) FirstName LastName 10 Venus Williams 11 Fernando Alonso 12 David Villa Sport ID (PK) Description 110 Tennis 111 Football 112 Formula1 Student_Sport ID_Student (PFK) ID_Sport (PFK) 10 110 11 111 11 112 12 111 5 <Student/ID=11> <Student> 11 Fernando Alonso rdf:type <Student/ID> <Student/LastName> <Student/FirstName>
- 6. R2RML ● Customized mappings ● Triples Map o Logical Table o Subject Map o Predicate Object Map Predicate Map Object Map Reference Object Map ● Term Map o constant o column o template 6 http://www.w3.org/TR/r2rml/
- 7. R2RML Example Student ID (PK) FirstName LastName 10 Venus Williams 11 Fernando Alonso 12 David Villa 7 <Estudiante/11> <Estudiante> Fernando Alonso rdf:type ex:fullName <#TriplesMap1> rr:logicalTable [ rr:tableName "Student" ]; rr:subjectMap [ rr:template "http://data.example.com/Estudiante/{ID}"; rr:class ex:Estudiante; ]; rr:predicateObjectMap [ rr:predicate ex:fullName; rr:objectMap [ rr:template "{FirstName} {LastName}" ]; ].
- 8. Background: M-N Relationship Expected Triples Student ID (PK) FirstName LastName 10 Venus Williams 11 Fernando Alonso 12 David Villa Sport ID (PK) Description 110 Tennis 111 Football 112 Formula1 Student_Sport ID_Student (PFK) ID_Sport (PFK) 10 110 11 111 11 112 12 111 8 <Student/ID=11> <Sport/ID=111> <Sport/ID=112> <Student#hasSport> <Student#hasSport>
- 9. Background: 1-N Relationship Expected Triples Student ID (PK) FirstName LastName 10 Venus Williams 11 Fernando Alonso 12 David Villa Sport ID (PK) Description 110 Tennis 111 Football 112 Formula1 Student_Sport ID_Student (PFK) ID_Sport (PFK) 10 110 11 111 11 112 12 111 Contact CID (PK) SID (FK) Email 1 10 venus@hotmail.com 2 10 venus@gmail.com 3 11 fernando@yahoo.com 4 12 david@msn.com 9 <Student/ID=10> <Contact/ID=2> <Student#hasContact> <Contact/ID=1> <Student#hasContact>
- 10. Background: IsA Relationship Expected Triples Student ID (PFK) FirstName LastName 10 Venus Williams 11 Fernando Alonso 12 David Villa Sport ID (PK) Description 110 Tennis 111 Football 112 Formula1 Student_Sport ID_Student (PFK) ID_Sport (PFK) 10 110 11 111 11 112 12 111 Person ID (PK) SSN 10 1234510 11 1234511 12 1234512 10 <Student/ID=10> 1234510 rdf:type <Student#SSN> <Person>
- 11. Goal ● To automatically generate R2RML mappings that: o simulate DM rules o encodes relationship in database 11 PINKEL, Christoph, et al. RODI: A Benchmark for Automatic Mapping Generation in Relational-to-Ontology Data Integration. Extended Semantic Web Conference 2015
- 12. MIRROR: Overview 1. Extraction of tables and its relationship 2. Mappings generation 12
- 13. Pruning Relationship Types 1 2 3 4 5 6 7 8 Parent (Mand, 1) (Mand, 1) (Mand, 1) (Mand, 1) (Mand, N) (Mand, N) (Mand, N) (Mand, N) Child (Mand, 1) (Mand, N) (Opt,1) (Opt, N) (Mand, 1) (Mand, N) (Opt,1) (Opt, N) 9 10 11 12 13 14 15 16 Parent (Opt, 1) (Opt, 1) (Opt, 1) (Opt, 1) (Opt, N) (Opt, N) (Opt, N) (Opt, N) Child (Mand, 1) (Mand, N) (Opt,1) (Opt, N) (Mand, 1) (Mand, N) (Opt,1) (Opt, N) Reflexive Property ● 2 = 5 ● 3 = 9 ● 4 = 13 ● 7 = 10 ● 8 = 14 ● 12 = 15 13 Primary key is not null and unique
- 16. Implementation & Experimentation ● Implementation o https://github.com/oeg-upm/MIRROR o morph-RDB integration https://github.com/oeg-upm/morph-rdb o Any R2RML engine ● Goal o 1st set mappings -> DM triples o 2nd mappings -> relationship triples ● Dataset o W3C DM Testcases 26 databases (D000 - D025) o Extension of D011 1-N M-N relationship ISA relationship 16
- 17. D011 Extension ● 1-N o Student - Contact ● IsA o Student - Person 17
- 18. D011: Generated Mappings 1st Set -> DM Triples 18
- 19. D011 Outputs DM 19 MIRROR + morph-RDB
- 20. D011: Generated Mappings 2nd Set -> M-N Relationship 20 <Sport/110> <SportHasStudent> <Student/10> . <Sport/111> <SportHasStudent> <Student/11> . <Sport/111> <SportHasStudent> <Student/12> . <Sport/112> <SportHasStudent> <Student/11> .
- 21. D011 Extension: Generated Mappings 2nd Set -> 1-N Relationship <Student/10> <StudenthasContact> <Contact/1> . <Student/10> <StudenthasContact> <Contact/2> . <Student/11> <StudenthasContact> <Contact/3> . <Student/12> <StudenthasContact> <Contact/4> . 21
- 22. D011 Extension: Generated Mappings 2nd Set -> IsA & inherited properties <Student/10> <rdf:type> <Person> . <Student/10> <Student#ssn> 1234510 . <Student/11> <rdf:type> <Person> . <Student/11> <Student#ssn> 1234511 . <Student/12> <rdf:type> <Person> . <Student/12> <Student#ssn> 1234512 . 22
- 23. Conclusion ● R2RML Mappings Generator o Implemented as MIRROR o Integrated with morph-RDB ● 2 Sets of Generated Mappings o Direct Mapping Triples o Encoded Relationship in a Database Schema ● Evaluation o Direct Mapping Test Cases o Extension of D011 23
- 24. MIRROR: Automatic R2RML Mapping Generation from Relational Databases Luciano Frontino de Medeiros Freddy Priyatna Oscar Corcho