The RDF output for an item currently contains only schema:dateModified (https://schema.org/dateModified). For example a recently created almost empty item.
SELECT ?property ?value WHERE {
wd:Q27895261 ?property ?value
}Gives
property value schema:version 409884566 schema:dateModified Nov 21, 2016 rdfs:label Washington (sigarenmerk)
Would be nice to also have the creation date of each item (and probably property too) in RDF as schema:dateCreated (https://schema.org/dateCreated). That way it's easier to make statistics.
I guess just asking the database for the first revision should be enough:
MariaDB [wikidatawiki_p]> SELECT rev_timestamp FROM page JOIN revision ON page_id=rev_page AND rev_parent_id=0 WHERE page_namespace=0 AND page_is_redirect=0 AND page_title='Q27895261'; +----------------+ | rev_timestamp | +----------------+ | 20161121034010 | +----------------+ 1 row in set (0.01 sec) MariaDB [wikidatawiki_p]> SELECT rev_timestamp FROM page JOIN revision ON page_id=rev_page AND rev_parent_id=0 WHERE page_namespace=0 AND page_is_redirect=0 AND page_title='Q42'; +----------------+ | rev_timestamp | +----------------+ | 20121029181848 | +----------------+ 1 row in set (0.64 sec)
Or should this task be preceded with a task to add the creation date as a page_prop ( https://www.mediawiki.org/wiki/Manual:Page_props_table ) and use that in the RDF dump? Having an easy and efficient way to get the creation date of a page might be of benefit for more use cases.