What is a database? Why does every single application we run into, except for maybe gateways, need one? Why are relational databases, despite over a decade of NoSQL advocacy, still reached for 80% of the time? What is querying? Joining? Referential integrity? Third normal form?A colleague years ago who led the database design team on a contract once told me, "SQL isn't rocket science." It's not. SQL and database design is actually kind of straight forward. There are reasons we do a...