demo/demo_caml.ml

   1 open Printf
   2 open Sqlite3
   3
   4 module G = Demo_caml_gen.Sqlgg(Sqlgg_sqlite3)
   5
   6 let explain msg db = printf "%s : %s\n" msg (errmsg db)
   7
   8 let main () =
   9   let db = db_open ":memory:" in
  10
  11   (* create tables *)
  12   G.create_person db;
  13   G.create_money db;
  14
  15   (* add all person records *)
  16   G.add_person db "John" "Black";
  17   let john = last_insert_rowid db in
  18   G.add_person db "Ivan" "Petrov";
  19   let ivan = last_insert_rowid db in
  20   G.add_person db "Sancho" "Alvares";
  21   let sancho = last_insert_rowid db in
  22
  23   (* add money relations *)
  24   G.add_money db john ivan 200L;
  25   G.add_money db ~src:john ~dst:sancho ~amount:100L;
  26   G.add_money db ~amount:250L ~dst:sancho ~src:john;
  27   G.add_money db sancho ivan 300L;
  28
  29   (* summarize by person and output *)
  30   print_endline "Total transfers:";
  31   G.calc_total db (fun ~fullname ~total -> printf "%s = %Lu\n" fullname total);
  32   printf "Total total: %Lu\n" (G.Fold.calc_total db (fun ~fullname:_ ~total acc -> Int64.add acc total) 0L);
  33
  34   (* list donors *)
  35   print_endline "Donors:";
  36   G.list_donors db "petrov" 100L (fun ~surname -> print_endline (match surname with Some s -> s | None -> "<unknown>"));
  37
  38   (* properly close database *)
  39   db_close db;
  40
  41   ()
  42
  43 let _ = Printexc.print main ()
  44