New subject: How to import Wikidata entities to another Wikibase

10 Aug 2018

Has anyone imported a subset of Wikidata into another Wikibase? How
did you do it?

I am working a project which wants to import Wikidata properties into
their Wikibase. I looked into how to do this, but I am hitting
roadblocks.

1) Fetching data
This part is easy, can do it via the API or dumps. If I only take
labels and descriptions and datatypes, then I don't even need to worry
about fetching any items referenced in the properties' properties.

2) Importing data
It's possible to create properties via api.php?action=wbeditentity,
but it does not allow specifying the id for new entities. We would
like to keep the ids same as in Wikidata for simplicity. I thought
that I would just create all properties up to P6000 or so, edit them
via the api, and then delete the unused properties. However, this
won't work because the property datatype must be specified at creation
time and cannot be changed afterwards.

Possible solutions:
a) Make it possible to specify the id of newly created entity (likely
guarded with a special right).
b) Make it possible to change property datatype after creation.
c) Drop the requirement of using the same ids in our wikibase.
d) Use a MediaWiki maintenance script where it is possible to bypass
restrictions and specify the id of the newly created entity.
Afterwards database must be updated manually to increase the tracker
for next free entity number to match the highest used id.
e) Avoid having to import properties (e.g. wait for support for
federated wikibases, implement an another storage mechanism that only
refers to Wikidata ids without having them in place.)

I am currently dreaming of (a) and probably going for (d) for which I
already have a rudimentary script. Any comments, suggestions or tips?

  -Niklas