A friend of mine, Cambridge graduate, a day or two ago needed to read about normalization.
We looked at the Wiki page.
https://en.wikipedia.org/wiki/Database_normalization
A huge page, and for someone who doesn't know what normalization is, totally and utterly useless in every possible way.
Hell, I've been using computers since I was a child, read the Date book, wrote my own relational database from scratch, and I don't know what some of the stuff on that page means. Explaining everything in terms which themselves need explanation is not useful, and it is the absolute hallmark of science wikipedia articles.
So what I would say is this : you can't learn from Wikipedia articles. They do not teach. Which makes me question their value. What are they for?