With 1 I was referring to the 6-8+ SELECTs everytime you post an image. It's getting rather slow, and I was hoping indexing parent would help. I can't comment yet on its effectiveness.

With (2), I see. I hadn't noticed the "preserve name" thing.

(3): From Wikipedia:
"The SQL standard is not freely available." WTF?
Anyway, idealism is overrated. You can discriminate against databases that don't support unsigned integers.