Relation databases are the jack-of-all-trades databases requiring tons of "switches and knobs" to adjust their behavior for the specific task. This is why we ha

Relation databases are the jack-of-all-trades databases requiring tons of "switches and knobs" to adjust their behavior for the specific task. This is why we have DBAs who specialize in this sort of thing. Many of the no-SQL databases are very task specific and, as such, don't have this problem. Probably one of the reasons for their popularity. Learning which no-SQL database is best for each task tends to be easier than learning how to tweak relation DBs for each task. I think part of the reason that relation DBs are coming back a bit is that this communication/documentation issue is starting to be addressed.