ISSUE-59: Syntactic sugar for triples maps that only have a single predicate-object map

simple-triples-maps

Syntactic sugar for triples maps that only have a single predicate-object map

State:

POSTPONED

Product:

R2RML

Raised by:

Richard Cyganiak

Opened on:

2011-07-29

Description:

Currently, a triples map has exactly one subject map, and then a number of predicate-object maps. However, there is a case that we can expect to see reasonably often where a triples map has exactly one predicate-object map. This is when an n:m link table is mapped to a single set of triples.

In the interest of making simple things simple and hard things possible, this case could be simplified by removing the intermediate predicate-object map node and just sticking its predicate map(s) and object map directly onto the triples map. This yields a much more readable form.

Example:

Student(s_id, name)
Course(c_id, title)
Enrolled(s_id, c_id)

Where Enrolled is the many-to-many relationship. The current R2RML mapping would be:

<#LinkMap_1_2>
rr:logicalTable [ rr:tableName "enrolled" ];
rr:subjectMap [ rr:template "http://data.example.com/student/{s_id}" ];
rr:predicateObjectMap [
rr:predicateMap [ rr:predicate ex:isEnrolled ];
rr:objectMap [ rr:template "http://data.example.com/course/{c_id}" ];
].

With syntactic sugar, it would become:

<#LinkMap_1_2>
rr:logicalTable [ rr:tableName "enrolled" ];
rr:subjectMap [ rr:template "http://data.example.com/student/{s_id}" ];
rr:predicateMap [ rr:predicate ex:isEnrolled ];
rr:objectMap [ rr:template "http://data.example.com/course/{c_id}" ].

The spec would say: A triples map MAY have exactly one object map and one or more predicate maps. If these are present, then they form an implicit predicate-object map. This would be a simple change.

This has been proposed by Richard here [1] and seconded by Juan here [2].

[1]: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011Jul/0169.html
[2]: http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011Jul/0170.html

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Related emails:

1. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
2. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
3. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
4. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
5. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
6. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
7. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
8. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
9. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
10. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
11. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
12. Re: LC publication (from souripriya.das@oracle.com on 2011-09-15)
13. Re: LC publication (from michael.hausenblas@deri.org on 2011-09-15)
14. Re: LC publication (from bvillazon@fi.upm.es on 2011-09-15)
15. Re: LC publication (from SOURIPRIYA.DAS@oracle.com on 2011-09-14)
16. Re: LC publication (from bvillazon@fi.upm.es on 2011-09-14)
17. Re: LC publication (from bvillazon@fi.upm.es on 2011-09-14)
18. Re: LC publication (from souripriya.das@oracle.com on 2011-09-14)
19. LC publication (from michael.hausenblas@deri.org on 2011-09-14)
20. Minutes of 2011-09-13 telecon (from michael.hausenblas@deri.org on 2011-09-13)
21. Re: RDB2RDF WG agenda for 2011-09-13 meeting 1600 UTC (from bvillazon@fi.upm.es on 2011-09-13)
22. RDB2RDF WG agenda for 2011-09-13 meeting 1600 UTC (from Michael.Hausenblas@deri.org on 2011-09-12)
23. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from dmcneil@revelytix.com on 2011-08-30)
24. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from richard@cyganiak.de on 2011-08-30)
25. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from boris.villazon@deri.org on 2011-08-30)
26. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from dmcneil@revelytix.com on 2011-08-30)
27. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from dmcneil@revelytix.com on 2011-08-29)
28. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from richard@cyganiak.de on 2011-08-29)
29. Re: Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from dmcneil@revelytix.com on 2011-08-29)
30. Please review: syntactic sugar and polishing (ISSUE-54, ISSUE-56, ISSUE-59, ISSUE-60) (from richard@cyganiak.de on 2011-08-27)
31. Re: Status of the R2RML document and going last call (from michael.hausenblas@deri.org on 2011-08-02)
32. Status of the R2RML document and going last call (from richard@cyganiak.de on 2011-08-02)
33. Re: RDB2RDF WG agenda for 2011-08-02 meeting 1600 UTC (from marcelo.arenas1@gmail.com on 2011-08-02)
34. Re: RDB2RDF WG agenda for 2011-08-02 meeting 1600 UTC (from ashok.malhotra@oracle.com on 2011-08-02)
35. RDB2RDF WG agenda for 2011-08-02 meeting 1600 UTC (from michael.hausenblas@deri.org on 2011-07-30)
36. Re: Many-to-Many table in R2RML (from juanfederico@gmail.com on 2011-07-29)
37. Re: Many-to-Many table in R2RML (from richard@cyganiak.de on 2011-07-29)
38. ISSUE-59 (simple-triples-maps): Syntactic sugar for triples maps that only have a single predicate-object map [R2RML] (from sysbot+tracker@w3.org on 2011-07-29)

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