https://github.com/ClearTables/ClearTables/issues/70 documents the ClearTables side of what needs doing
One question is if we want to handle the case of an OSM object having multiple Wikidata IDs. Wikidata IRIs have a many to many relationship with OSM features, but in practice very few features have multiple IDs tagged. My inclination is to only handle the common case of one wikidata ID.
The other question is what datatype to use for an ID. I can't find any information if we need a 32-bit number, 64-bit number, or numeric type with no maximum size.