I’m a tech interested guy. I’ve touched SQL once or twice, but wasn’t able to really make sense of it. That combined with not having a practical use leaves SQL as largely a black box in my mind (though I am somewhat familiar with technical concepts in databasing).
With that, I keep seeing [pic related] as proof that Elon Musk doesn’t understand SQL.
Can someone give me a technical explanation for how one would come to that conclusion? I’d love if you could pass technical documentation for that.
This sounds like a reasonable argument.
Can you pass any resources with examples on when having duplicate values would be useful/best practices?
Sure, basically any time you have a many-to-many relationship you’ll have to repeat keys multiple times. Think students taking courses. You’d have a students table and a courses table, but the relationship is many students take many courses. So you’d want a third table for lookups where each row is [student_id, course_id].
This stackoverflow post has a similar example with authors and books - https://stackoverflow.com/questions/13970628/how-do-i-model-a-many-to-many-relation-in-sql-server#13970688