adamc@419: functor Make(M : sig
adamc@419:                  type data
adamc@419:                  val inj : sql_injectable data
adamc@419:              end) = struct
adamc@419: 
adamc@419:     type ref = int
adamc@419: 
adamc@419:     sequence s
adamc@419:     table t : { Id : int, Data : M.data }
adamc@419: 
adamc@419:     fun new d =
adamc@419:         id <- nextval s;
adamc@471:         dml (INSERT INTO t (Id, Data) VALUES ({[id]}, {[d]}));
adamc@419:         return id
adamc@419: 
adamc@419:     fun read r =
adamc@471:         o <- oneOrNoRows (SELECT t.Data FROM t WHERE t.Id = {[r]});
adamc@501:         case o of
adamc@419:             None => error <xml>You already deleted that ref!</xml>
adamc@501:           | Some r => return r.T.Data
adamc@419: 
adamc@419:     fun write r d =
adamc@471:         dml (UPDATE t SET Data = {[d]} WHERE Id = {[r]})
adamc@419: 
adamc@419:     fun delete r =
adamc@471:         dml (DELETE FROM t WHERE Id = {[r]})
adamc@420: 
adamc@419: end