The problem, I think is that most people, me included, don't really know what databases really do. There is a whole lot about optimizing procedural code, with a variety of tools, the dangers of premature optimization and the tradeoff with readability. Anyone with a computer science degree has heard about algorithmic complexity, caches, etc...

But databases are just magic. You try things out, usually involving a CREATE INDEX at some point, and sometime it gets faster, so you keep it.

Rachel, in he blog post is a good example of that thought process. She used a "best practice", added an index (there is always an index) and it made her queries faster, cool. I don't blame her, it works, and it is a good reminder of the 3NF principle. But work like that on procedural code and I'm sure we will get plenty of reactions like "why no profiler?".

Many, many programmers write SQL, but very few seem to know about query plans and the way the underlying data structures work. It almost looks like secret knowledge of the DBA caste or something. I know it is all public knowledge of course, but it is rarely taught, and the little I know about is is all personal curiosity.