W3C home > Mailing lists > Public > public-gld-wg@w3.org > January 2013

Re: AW: ISSUE-30 (CubeRel): Declaring relations between cubes [Data Cube Vocabulary]

From: Dave Reynolds <dave.e.reynolds@gmail.com>
Date: Thu, 17 Jan 2013 14:47:09 +0000
Message-ID: <50F80EED.6040201@gmail.com>
To: public-gld-wg@w3.org
Hi Benedikt,

I would need to study QB4OLAP property before commenting in detail on that.

However, this issue was deliberately framed as about *declaring* the 
relationship between cubes. Such a declarative statement would be 
different from a procedural description of a set of transformations 
which have actually taken place - which is what I understand Cogs to be 
about.

As a high level observation, the working group has very limited time and 
capacity left so we should focus on getting a sufficient version of the 
core of QB agreed. My recommendation on Issue-30 is, in fact, that we 
should postpone to a future iteration. There is a genuine requirement 
here, and QB4OLAP looks good, but I'm not sure we have sufficient 
experience with it and sufficiently working group bandwidth to properly 
address this area, this time around.

Dave

On 11/01/13 13:27, Benedikt Kaempgen wrote:
> Hi,
>
> Regarding this issue, I would like to point to the suggestion of [1]. Here, the component specification of a measure can define an aggregation function that should be used when aggregating measures to a higher level.
>
> A vocabulary that may be used for data transformations to statistical data is Cogs [2].
>
> Again, I have added a recommendation to [3]: "There should be a recommended way of declaring relations between cubes"
>
> Best,
>
> Benedikt
>
> [1] QB4OLAP: a Vocabulary for Business Intelligence over the Semantic Web. <http://publishing-multidimensional-data.googlecode.com/git/index.html>
> [2] Cogs. ETL Provenance Vocabulary. <https://sites.google.com/site/cogsvocab/>
> [3] <http://www.w3.org/2011/gld/wiki/Data_Cube_Vocabulary/Use_Cases#There_should_be_a_recommended_way_of_declaring_relations_between_cubes>
>
> ________________________________________
> Von: Government Linked Data Working Group Issue Tracker [sysbot+tracker@w3.org]
> Gesendet: Freitag, 17. Februar 2012 17:03
> An: public-gld-wg@w3.org
> Betreff: ISSUE-30 (CubeRel): Declaring relations between cubes [Data Cube Vocabulary]
>
> ISSUE-30 (CubeRel): Declaring relations between cubes [Data Cube Vocabulary]
>
> http://www.w3.org/2011/gld/track/issues/30
>
> Raised by: Dave Reynolds
> On product: Data Cube Vocabulary
>
> In some situations statistical data sets are used to derive further datasets. Should Data Cube be able to explicitly convey these relationships?
>
> A simple specific use case is that the Welsh Assembly government publishes a variety of population datasets broken down in different ways. For many uses then population broken down by some category (e.g. ethnicity) is expressed as a percentage. Separate datasets give the actual counts per category and aggregate counts.  In such cases it is common to talk about the denominator (often DENOM) which is the aggregate count against which the percentages can be interpreted.
>
> Should Data Cube support explicit declaration of such relationships either between separated qb:DataSets or between measures with a single qb:DataSet (e.g. ex:populationCount and ex:populationPercent)?
>
> If so should that be scoped to simple, common relationships like DENOM or allow expression of arbitrary mathematical relations?
>
> Note that there has been some work towards this within the SDMX community as indicated here: http://groups.google.com/group/publishing-statistical-data/msg/b3fd023d8c33561d
>
>
>
>
Received on Thursday, 17 January 2013 14:47:41 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 25 June 2013 15:04:58 UTC