It's everywhere! No object orientation. Causes problems especially when you have components that provide base view names and columns names, etc. and other components that pass around SQL fragments to build queries or, worse, depend on public or protected access to constant view names/columns, etc. in other components. How to pass this stuff around in an OO manner? How to externalize it in a pattern-like way?  How to encapsulate it?

Closest thing I've seen to a solution is the Query Object pattern in Martin Fowler's P of EAA.