I wrote a new Tcl procedure db_dfs (dfs = depth-first search) that
simulates Oracle's "connect by" query. It works similar to db_foreach.
See http://dev.arsdigita.com/connect_by.tcl
Please let me know what you think. If this is a move in the right
direction, we could replace all calls of db_foreach that use a
"connect by" clause with the corresponding call of "db_dfs".
Then, we could provide two versions of db_dfs: one for Postgres
that simulates the "connect by" with a recursive algorithm and
one for Oracle that uses "connect by" as before.
