ISSUE-70: Behaviour of fully qualified column names in rr:sqlQuery


Behaviour of fully qualified column names in rr:sqlQuery

Raised by:
Richard Cyganiak
Opened on:
This was raised by David as part of his LC feedback:

Section 6 of R2RML states:

The referenced columns of all term maps of a triples map (subject map, predicate maps, object maps, graph maps) MUST be column names that exist in the term map's logical table.

Per the previous definition of "column name" this implies that the values cannot be qualified. And the intent is indeed that in rr:column, rr:template etc, "JOB" would be used and "EMP.JOB" would be illegal.

But does this mean that writing "SELECT EMP.JOB FROM JOB" in rr:sqlQuery should be considered illegal? Or does it make sense to write such a query and then access the result set column with just an unqualified "JOB"?
Related Actions Items:
Related emails:
  1. Status update on LC comments and post-LC changes to R2RML (from on 2011-11-07)
  2. ISSUE-70 (SELECT EMP.JOB): Behaviour of fully qualified column names in rr:sqlQuery (from on 2011-11-07)

Related notes:

(There was no WG discussion or WG resolution on the issue.)

Editor addressed this by allowing fully qualified column names in SQL queries as long as there's no clash in the column name. So, SELECT EMP.ID is ok, but SELECT EMP.ID, DEPT.ID is not.

Spec was Updated accordingly, and examples added.

Richard Cyganiak, 20 Dec 2011, 17:46:35

The change was announced on the comments list (not WG list) here:

Richard Cyganiak, 20 Dec 2011, 17:51:33

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