ISSUE-9: Generate Blank Nodes for duplicate tuples

bn_directmapping

Generate Blank Nodes for duplicate tuples

State:

POSTPONED

Product:

Direct Mapping

Raised by:

Juan Sequeda

Opened on:

2011-01-21

Description:

Given a table that does not have a primary key, which has duplicate tuples, a different blank node must be created for each tuple.

In the Direct Mapping as rules section of the Direct Mapping document, we described this scenario by using all the values of the tuple to create the blank node [1] [2]. However, there is a bug, raised by Alexandre [3]. The issue is that datalog cannot deal with duplicate. Consequently, Marcelo raised the point that we can use simple versions of datalog that can deal with duplicate solutions.

Possible solutions:

1) assume that each table implicitly has a row id which is part of its set of attributes. The row id is unique.
2) associates to each tuple an annotation that corresponds to the multiplicity of the tuple in the database. This annotation function corresponds to the function card in the definition of the semantics of SPARQL


[1] http://www.w3.org/TR/2010/WD-rdb-direct-mapping-20101118/#rules_table_triples_no_pk
[2] http://www.w3.org/TR/2010/WD-rdb-direct-mapping-20101118/#rules_literal_triples_no_pk
[3] http://lists.w3.org/Archives/Public/public-rdb2rdf-wg/2011Jan/0044.html

Related Actions Items:

No related actions

Related emails:

1. Re: Minutes of 2011-03-15 telecon (from eric@w3.org on 2011-03-17)
2. Minutes of 2011-03-15 telecon (from michael.hausenblas@deri.org on 2011-03-15)
3. Re: RDB2RDF WG agenda for 2011-03-15 meeting 1600 UTC (from bvillazon@fi.upm.es on 2011-03-15)
4. Re: RDB2RDF WG agenda for 2011-03-15 meeting 1600 UTC (from juanfederico@gmail.com on 2011-03-15)
5. Re: RDB2RDF WG agenda for 2011-03-15 meeting 1600 UTC (from marcelo.arenas1@gmail.com on 2011-03-15)
6. RDB2RDF WG agenda for 2011-03-15 meeting 1600 UTC (from michael.hausenblas@deri.org on 2011-03-15)
7. Minutes of 2011-03-08 telecon (from michael.hausenblas@deri.org on 2011-03-08)
8. Re: RDB2RDF WG agenda for 2011-03-08 meeting 1700 UTC (from michael.hausenblas@deri.org on 2011-03-08)
9. Re: RDB2RDF WG agenda for 2011-03-08 meeting 1700 UTC (from bertails@w3.org on 2011-03-07)
10. RDB2RDF WG agenda for 2011-03-08 meeting 1700 UTC (from michael.hausenblas@deri.org on 2011-03-06)
11. Minutes of 2011-03-01 telecon (from michael.hausenblas@deri.org on 2011-03-01)
12. Re: Test cases to check (from ivan@w3.org on 2011-02-03)
13. Re: ISSUE-9 Another question about Generate Blank Nodes (from phayes@ihmc.us on 2011-02-02)
14. Re: Test cases to check (from eric@w3.org on 2011-02-02)
15. Fwd: Re: ISSUE-9 Another question about Generate Blank Nodes (from souripriya.das@oracle.com on 2011-02-02)
16. Re: ISSUE-9 Another question about Generate Blank Nodes (from ivan@w3.org on 2011-02-02)
17. Re: ISSUE-9 Another question about Generate Blank Nodes (from ivan@w3.org on 2011-02-02)
18. Re: ISSUE-9 Another question about Generate Blank Nodes (from eric@w3.org on 2011-02-02)
19. Re: ISSUE-9 Another question about Generate Blank Nodes (from auer@informatik.uni-leipzig.de on 2011-02-02)
20. Re: ISSUE-9 Another question about Generate Blank Nodes (from SOURIPRIYA.DAS@oracle.com on 2011-02-01)
21. Re: ISSUE-9 Another question about Generate Blank Nodes (from eric@w3.org on 2011-02-01)
22. Re: ISSUE-9 Another question about Generate Blank Nodes (from bertails@w3.org on 2011-02-01)
23. Re: ISSUE-9 Another question about Generate Blank Nodes (from ashok.malhotra@oracle.com on 2011-02-01)
24. Re: ISSUE-9 Another question about Generate Blank Nodes (from bertails@w3.org on 2011-02-01)
25. Re: ISSUE-9 Another question about Generate Blank Nodes (from auer@informatik.uni-leipzig.de on 2011-02-01)
26. Re: Test cases to check (from eric@w3.org on 2011-02-01)
27. Re: Test cases to check (from ivan@w3.org on 2011-02-01)
28. Test cases to check (from bvillazon@fi.upm.es on 2011-02-01)
29. Re: ISSUE-9 Another question about Generate Blank Nodes (from juanfederico@gmail.com on 2011-01-31)
30. Re: ISSUE-9 Another question about Generate Blank Nodes (from eric@w3.org on 2011-01-31)
31. ISSUE-9 Another question about Generate Blank Nodes (from juanfederico@gmail.com on 2011-01-31)
32. Re: ISSUE-9 (bn_directmapping): Generate Blank Nodes for duplicate tuples [Direct Mapping] (from juanfederico@gmail.com on 2011-01-31)
33. ISSUE-9 (bn_directmapping): Generate Blank Nodes for duplicate tuples [Direct Mapping] (from sysbot+tracker@w3.org on 2011-01-21)

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