To make datasets more findable and databases more interoperable, it is recommended to share not just top-level metadata, but also record-level metadata. For example, for chemical databases, one may share the chemical compound identifiers as open data, while keeping the data itself in their own database. That allows other resources, like Wikidata, to link to a private database. First, that makes such data more findable, but it also makes the same data easier to integrate, and therefore more interoperable.