- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Sun, 22 Apr 2012 23:30:00 +0100
- To: W3C RDB2RDF <public-rdb2rdf-wg@w3.org>
Section 5.2 sates: [[ Any columns in the SELECT list derived by projecting an expression MUST be named. ]] http://www.w3.org/TR/2012/CR-r2rml-20120223/#r2rml-views I propose to replace this with an informative note: [[ Note: Any columns in the SELECT list derived by projecting an expression should be explicitly named because otherwise they cannot be referenced in the rest of the mapping. ]] Rationale: To detect that a SQL query violates the “MUST” criteria, a processor would have to parse and understand the query, which is a cost for implementations. This cost brings little benefit, because unnamed columns (i.e., the DB implementation picks a name) are merely useless in an R2RML mapping, but not actively harmful. Best, Richard
Received on Sunday, 22 April 2012 22:30:36 UTC