Well the thing about mySQL is that its own database to manage users and user database information is hideous. Maybe its ok if you use a graphic admin tool, but the actual dirty work behind it is nasty.
As for Oracle. well thats the biggest load of overcomplicated zoo produce I've ever had the misfortune to see.
and Microsoft SQL server "Lets try and confuse people by using buzzwords in our product names" uck.
BUT none of this is even close to the question, database THEORY.
all DB servers and the SQL language may be interesting but have absolutely nothing to do with the theory, because they all do it wrongly.
So how does this make you feel about Cascading Style Sheets?
-PaulBastard :)