There are a lot of books on database system design like »Fundamentals of Database Systems« [1] by Elmasri and Navathe. The reason there is no such thing as a simple tutorial is because any serious attempt to build a database system will consume on the order of tens or hundreds of men-years of effort if you start from scratch.

[1] http://www.amazon.com/Fundamentals-Database-Systems-Ramez-El...

The problem with the standards is that getting copies costs actual money. If one really wants to start learning about databases, it can be very difficult to decide what to pay for. Implementation documentation, at least, is generally free.

For books, I've heard good things about http://www.amazon.com/Fundamentals-Database-Systems-Ramez-El..., though I haven't read it myself.