Scientific Articles are in a similar situation: when importing one from a bibliography database, you won't always find every author... So people made an alternative prop "author name" and some disambiguation tools that allow users to gradually replace those with "author" links to real persons.
Let's put aside the question whether each song ever written should be in WD: I believe all of this data, modeled more elaborately, is available on MusicBrainz. There's a difference between a work (eg "Both Sides Now") and its particular rendition in an album (as you said that track is "a cover"), and MusicBrainz makes that distinction and captures both, but I think WD doesn't (I don't work on music in WD, so I haven't checked).
If you really want all this data in WD then I guess you could import it from MusicBrainz... a massive undertaking.
> Wikidata's own parser (however it works)
There's no such thing (in contrast, DBpedia has the dbpedia extraction framework, which is fairly good but not perfect and suffers greatly from the various ways people use to describe the same thing). WD has tools like QS and wikibase-cli, and people write bots to scrape and contribute specific kinds of data.
Let's put aside the question whether each song ever written should be in WD: I believe all of this data, modeled more elaborately, is available on MusicBrainz. There's a difference between a work (eg "Both Sides Now") and its particular rendition in an album (as you said that track is "a cover"), and MusicBrainz makes that distinction and captures both, but I think WD doesn't (I don't work on music in WD, so I haven't checked).
If you really want all this data in WD then I guess you could import it from MusicBrainz... a massive undertaking.
> Wikidata's own parser (however it works)
There's no such thing (in contrast, DBpedia has the dbpedia extraction framework, which is fairly good but not perfect and suffers greatly from the various ways people use to describe the same thing). WD has tools like QS and wikibase-cli, and people write bots to scrape and contribute specific kinds of data.
BTW the Wikipedia link https://en.wikipedia.org/wiki/Both_Sides,_Now#Other_recordin... is wrong (invalid): you can't have two anchors in a link.
Cheers!