ISSUE-71: Column name collisions between child and parent queries in RefObjectMaps

child-parent-collision

Column name collisions between child and parent queries in RefObjectMaps

State:

CLOSED

Product:

R2RML

Raised by:

Richard Cyganiak

Opened on:

2011-11-07

Description:

This is part of David's Last Call comments:
http://lists.w3.org/Archives/Public/public-rdb2rdf-comments/2011Oct/0022.html

R2RML Section 8 states:

[[
SELECT * FROM ({child-query}) AS child, ({parent-query}) AS parent
]]

From a SQL perspective, this feels wrong because it doesn't address the issue of column name collisions between the child and parent query.

Is the thought that we can just ignore this because we describe in section 11 that the projected columns are split between child and parent?

This seems to be not fully thought through. I think either the spec needs something that states that the sets of columns are disjoint (but that would limit the usefulness), or the mechanics in sections 8 and 11 need to be changed.

Related Actions Items:

• ACTION-171 on Richard Cyganiak to Check whether ISSUE-71 can be addressed using a SQL query that returns row types - due 2011-11-21, closed

Related emails:

1. Status update on LC comments and post-LC changes to R2RML (from richard@cyganiak.de on 2011-11-07)
2. ISSUE-71 (child-parent-collision): Column name collisions between child and parent queries in RefObjectMaps [R2RML] (from sysbot+tracker@w3.org on 2011-11-07)

Related notes:

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