Good Lord I wish more people understood which elements of RDBs are essential features of the logic they’re based on; which ones are results of the way the relat

Good Lord I wish more people understood which elements of RDBs are essential features of the logic they’re based on; which ones are results of the way the relational model screwed up the logic it was supposed to be based on (hello there, Closed World Assumption); which ones are results of the way SQL screwed up the relational model; and which ones are just elements of a performance and security model that is quite independent of the logic (eg. there’s nothing in the logic which dictates that adding a row is routine but adding a table is a Big Deal). It probably doesn’t qualify as a delightful subject, but it would be a great service if someone could explain this stuff to people.