Support export rdf graph in CSV format

[weiranfu]

Hey,

I noticed that currently export-rdf only supports exporting files in format of turtle, nquads, ntriples, neptuneStreamsJson and neptuneStreamsSimpleJson. Is it possible to support exporting files in CSV format? So that we can using SELECT tuple queries in SPARQL and export results in CSV format to be used by data warehouse.
DW usually doesn't have a good support for files in RDF format.

Seems it already supports tuple queries but io doesn't support CSV writer.

Thanks,
Weiran

[Cole-Greer]

Hi @weiranfu,

We will look into adding CSV support for RDF exports. Just to ensure that we are on the same page, would you expect the exported CSV to be a fixed 4 column (S,P,O,G) output such as:

s1,p1,o1,g1
s2,p2,o2,g2

Thanks,
Cole

[weiranfu]

Hey Cole,

Thanks for your response.
I think the result can have arbitrary columns. For example, we put n IRI in the SELECT closure, we will have n columns in CSV with headers.

Thanks,
Weiran

[charlesivie]

This implies a use case where the export is the result of a SPARQL Select query, and not of a CONSTRUCT query.
I would suggest that a user could choose CSV for query; if it is a SELECT query, use the column names as the header in the CSV, if it is a CONSTRUCT query, create a csv header of subject, predicate, object.

[weiranfu]

yes @charlesivie