> Tutorials show harmful patterns.
Try to find a sample SQL database, for any vendor, that does not employ artificial table primary keys. This was a requirement in the 1980s so that your queries would execute before the heat death of the universe, but that has not been the case for decades. Microsoft is particularly guilty of this. Artificial keys are an anti-pattern. (And, btw, there's a dearth of literature on why artificial keys are an anti-pattern.)
Here's the only sample database I know of that consistently uses natural keys across all tables, created by a SQL educator who knows his stuff.