ISSUE-35: Case sensitivity of SQL identifiers

case sensitivity

Case sensitivity of SQL identifiers

State:
CLOSED
Product:
R2RML
Raised by:
David McNeil
Opened on:
2011-03-22
Description:
In several places the R2RML spec indicates the SQL identifiers (e.g. column names) are case sensitive (e.g. section 3.3.1.8). I believe that it would be more useful to specify that the case sensitivity of the SQL identifiers needs to match the case sensitivity of the underlying database. So if the database is case _in_sensitive then it is acceptable (and good) for an R2RML implementation to interpret the SQL identifiers in a case _in_sensitive matter.

Treating the identifiers as case _in_sensitive when the underlying database is case _in_sensitive is useful for a couple of reasons:
* users of such a database are accustomed to writing case _in_sensitive SQL
* user entered SQL identifiers need to be interpreted in a way that matches the identifiers generated by the underlying database. For example, the database produces SQL identifiers when the database metadata is queried.

This issue arises in an R2RML implementation that parses the SQL in the R2RML mapping and performs validation, data type analysis, etc.

A possible way to address this is to add a section to the spec that states the "execution environment" should include an indicator of whether the underlying database is case sensitive. This is how we have addressed this issue in our implementation.

Related Actions Items:
No related actions
Related emails:
  1. Re: SQL delimited vs regular identifiers (from souripriya.das@oracle.com on 2011-10-18)
  2. SQL delimited vs regular identifiers (from dmcneil@revelytix.com on 2011-10-13)
  3. Re: Implemented ISSUE-35 resolution on quoting and case sensitivity of identifiers (from dmcneil@revelytix.com on 2011-07-13)
  4. Implemented ISSUE-35 resolution on quoting and case sensitivity of identifiers (from richard@cyganiak.de on 2011-07-13)
  5. Minutes of 2011-07-12 telecon (from michael.hausenblas@deri.org on 2011-07-12)
  6. Re: Agenda for July 12 Telcon (from michael.hausenblas@deri.org on 2011-07-12)
  7. Re: Agenda for July 12 Telcon (from juanfederico@gmail.com on 2011-07-12)
  8. Re: Agenda for July 12 Telcon (from privera.salas@gmail.com on 2011-07-12)
  9. Re: Agenda for July 12 Telcon (from marcelo.arenas1@gmail.com on 2011-07-12)
  10. Agenda for July 12 Telcon (from ashok.malhotra@oracle.com on 2011-07-09)
  11. Fun with inverse expressions (from richard@cyganiak.de on 2011-07-05)
  12. Proposed resolution for ISSUE-35 (case sensitivity) (from richard@cyganiak.de on 2011-05-10)
  13. Re: case sensitive vs insensitive (from richard@cyganiak.de on 2011-05-10)
  14. Re: RDB2RDF WG agenda for 2011-03-29 meeting 1600 UTC (from privera.salas@gmail.com on 2011-03-29)
  15. Re: RDB2RDF WG agenda for 2011-03-29 meeting 1600 UTC (from nuno.lopes@deri.org on 2011-03-29)
  16. Re: RDB2RDF WG agenda for 2011-03-29 meeting 1600 UTC (from richard@cyganiak.de on 2011-03-25)
  17. Re: RDB2RDF WG agenda for 2011-03-29 meeting 1600 UTC (from ivan@w3.org on 2011-03-25)
  18. RDB2RDF WG agenda for 2011-03-29 meeting 1600 UTC (from michael.hausenblas@deri.org on 2011-03-25)
  19. ISSUE-35 (case sensitivity): Case sensitivity of SQL identifiers [R2RML] (from sysbot+tracker@w3.org on 2011-03-22)

Related notes:

RESOLUTION: Resolve ISSUE-35 by allowing use of quotes around SQL
column/table identifiers in the mapping language; requiring that
authors match the quoting style that was used when creating the
identifier; follow SQL rules for case sensitivity (quoted is case
sensitive; unquoted is case insensitive)
http://www.w3.org/2011/07/12-rdb2rdf-minutes.html

Implemented here:
http://www.w3.org/2001/sw/rdb2rdf/r2rml/#dfn-sql-identifier

Richard Cyganiak, 13 Jul 2011, 11:27:11

I think the case sensitivity needs to be handled at the identifier level (i.e. not at the database level as this issue originally described). So I agree with how we are planning to handle this now in R2RML, by treating unquoted identifiers in R2RML as "regular identifiers" and quoted identifiers as "delimited identifiers"

David McNeil, 3 Nov 2011, 19:00:12

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Ashok Malhotra <ashok.malhotra@oracle.com>, Michael Hausenblas <michael.hausenblas@deri.org>, Chairs, Eric Prud'hommeaux <eric@w3.org>, Ivan Herman <ivan@w3.org>, Staff Contacts
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