Review of R2RML working draft

Hi all,

As promised I started carefully reading the current working draft. In
general the document looks quite good. Hence most of my comments are
relatively minor issues and typos. Attached are my comments and revision
requests for the first half, i.e. sections 1-5 of the R2RML spec. I will
send comments for the remaining sections later this week. Unfortunately,
I might not be able to participate in tomorrow's call, since I'm
currently on holiday in rural Russia, with flaky Internet and mobile



1 Introduction

* "The intended audience of this specification are implementors of ..."
=> "The intended audience of this specification IS implementors of "

1.1 Document Conventions

* "Blue tables are example input into an R2RML mapping:" => "Blue tables
contain example input into an R2RML mapping:"

2 R2RML Overview and Example (Informative)

* I would move the "or" in beginning of the last enum item of logical
tables to the end of the previous one

2.3 A Mapping for the Example Database

* it is unclear what is actually meant here with "rr:parentTriplesMap
<#TriplesMap2>;" and how this referencing works - we should add few more
sentences as explanation here

4 R2RML Processors and Mapping Documents

* "A SQL connection to ..." => "An SQL connection to ..."
* remove "to" in "without an explicit to catalog or schema reference"
* concatentation => concatenation
* "The base IRI MUST be a valid IRI." -- base IRI was not yet introduced
here, maybe we should have an introductory sentence before that like
"Each mapping has an associated base URI."
* "a SQL connection" => "an SQL connection" <- this might have to
replaced everywhere throughout the doc

4.1 Mapping Graphs and the R2RML Vocabulary

* "SHOULD NOT include any IRIs that start with the rr: namespace IRI,
but are not in the R2RML vocabulary." => "SHOULD NOT include any IRIs
that start with the rr: namespace IRI, but are not DEFINED in the R2RML
* specificaton => specification
* add full stop behind "(in other words, are “unused”)"

4.2 RDF-based Turtle Syntax; Media Type

"An R2RML mapping document is any document written in the Turtle RDF
syntax that encodes an R2RML mapping graph."

I guess this was discussed already during the telco, but do we really
require a mapping to be in the Turtle syntax - what's the purpose of
using RDF then - from my POV all valid RDF serializations should be
When reading a little further there is even a contradiction with the
following sentence:

"A conforming R2RML processor MUST accept R2RML mapping documents in
Turtle syntax. It MAY accept R2RML mapping graphs encoded in other RDF

I think its good to require all R2RML processors to support Turtle, but
I would still allow R2RML mapping graphs encoded in other RDF syntaxes
to be called R2RML mapping documents.

* "@prefix : <#>" - is not very illustrative for a novice user, maybe
rather "@prefix : <>"

4.3 Data Errors

* shouldn't "however" here and everywhere else in the document be
enclosed by commas?!

5 Defining Logical Tables

* again replace "A SQL ..." by "An SQL ..." everywhere
* I would not introduce a new term "SQL query-based table" here, since
it is nothing else than an SQL query -- why not just writing "SQL query"
instead and confuse the reader less. After all we just emulate the
creation of views here in R2RML, in order to not require the privilege
for the creation of real views.
* euqivalent => equivalent
* This section reads quite over-complicated and confusing to the casual
reader. Maybe we should add an explanation here such as "R2RML emulates
the creation of views, in order to not require the privilege for the
creation of real views in the underlying DBMS."

Received on Monday, 25 July 2011 10:16:17 UTC