Behavior of Table Groups when starting with CSV

[gkellogg]

One detail which was not resolved on #314 was how to handle discovered metadata which describes more than one table when starting with a CSV.

The resolved behavior states that if starting with a CSV, look for the first metadata found from link-, file- and directory-specific locations, in addition to user-provided flags and embedded metadata. One of the issues discussed was what do do if such metadata describes a TableGroup with additional tables:

From @iherman:

Indeed, what is the use, in the merge algorithm, of adding new tables when merging table groups (ie, the value of "resource")? Isn't it correct that, in both cases, those additional table descriptions will be ignored? In the case of the 'start by CSV' because only the table description for that single CSV file will be considered; in the case of the 'start by Metadata' because that situation simply does not occur. Maybe worth simplifying the merge algorithm on that point?

I tend to agree that if starting with a CSV, other tables are ignored and the transformed output should not include a TableGroup description (although, this may be a separate issue).

[JeniT]

The scenario that I always think of here is one like http://w3c.github.io/csvw/csv2json/#example-public-sector-roles-and-salaries where the interrelationships within the table are really important to give a full picture of what's going on.

In my opinion, if you start with a CSV and discover a metadata file that contains descriptions of other tables, then you should merge in the embedded metadata of those other tables to the metadata file.

[gkellogg]

... And generate RDF/JSON for all references tables, and the table group?

If you had a large number of tables, but you were interested in the output for just one of them, as might be intended by simply referencing the CSV, this might result in a lot of unintended output.

[danbri]

discussion: http://www.w3.org/2015/03/18-csvw-irc#T15-40-36

[iherman]

Decision: RESOLVED: starting from a CSV file generates the same table model as starting from the metadata file that the CSV file references