disclaimer: i have not yet implemented any of the storage methods other than the adjacency model (primarily because i could never understand them well enough to be able to write a query without having several reference books available -- they're just too hard)
maybe it's me, but the "path-string" column sure looks like the dreaded bogeyman to-be-avoided-at-all-cost multiple-values-in-a-single-column non-first-normal-form terrible design that all sql gurus, including some guy named celko, have been warning us for years never to implement...
what is the essential difference between 'ABD' and 'A/B/D' and 'A,B,D'?
yet we jump all over php programmers who want to store values like 'A,B,D' in a column
why aren't the path strings normalized into multiple rows like they should be?
or would that be too inconvenient?