console

# 以下ghci
# まずは結果を適当な名前(mrlout)を付けて記録
# それを対象にfindとかでqueryを投げる
# rSortは結局なにに使うのかわからなかった
> (Right cursor) <- access' $ DB.runMR' mapReduce {DB.rOut = DB.Output DB.Replace "mrlout" Nothing}
>(Right result) <- access' $ DB.find (DB.select [] "mrlout") {DB.sort=["value"=:1]}

DB.hs

dbname = "hoge"

access' action = do
  pipe <- DB.runIOE $ DB.connect (DB.host "localhost")
  DB.access pipe DB.master dbname action

mapFn = Bson.Javascript [] "function() {for(i in this.category) {emit(this.category[i], 1);}}"
reduceFn = Bson.Javascript [] "function(p, cur) {var c=0; for(i in cur){c+= cur[i];}; return c;}"
mapReduce = DB.mapReduce "Pkg" mapFn reduceFn