balance.sml

   1 structure Balance :> BALANCE =
   2 struct
   3
   4 open Util Sql Init
   5
   6
   7 (* Managing balances *)
   8
   9 type balance = {id :int, name : string, amount : real}
  10
  11 fun mkBalanceRow [id, name, amount] =
  12     {id = C.intFromSql id, name = C.stringFromSql name, amount = C.realFromSql amount}
  13   | mkBalanceRow row = Init.rowError ("balance", row)
  14
  15 fun addBalance name =
  16     let
  17         val db = getDb ()
  18         val id = nextSeq (db, "BalanceSeq")
  19     in
  20         C.dml db ($`INSERT INTO Balance (id, name, amount)
  21                     VALUES (^(C.intToSql id), ^(C.stringToSql name), 0.0)`);
  22         id
  23     end
  24
  25 fun lookupBalance id =
  26     let
  27         val c = getDb ()
  28     in
  29         (case C.oneOrNoRows c ($`SELECT id, name, amount FROM Balance WHERE id = ^(C.intToSql id)`) of
  30              NONE => raise Fail "Balance not found"
  31            | SOME r => mkBalanceRow r)
  32     end
  33
  34 fun modBalance (balance : balance) =
  35     let
  36         val db = getDb ()
  37     in
  38         ignore (C.dml db ($`UPDATE Balance
  39                             SET name = ^(C.stringToSql (#name balance))
  40                             WHERE id = ^(C.intToSql (#id balance))`))
  41     end
  42
  43 fun deleteBalance id =
  44     ignore (C.dml (getDb ()) ($`DELETE FROM Balance WHERE id = ^(C.intToSql id)`))
  45
  46 fun listBalances () =
  47     C.map (getDb ()) mkBalanceRow ($`SELECT id, name, amount FROM Balance
  48                                    ORDER BY name`)
  49
  50 fun validBalanceName name =
  51     size name <= 20
  52     andalso CharVector.all (fn ch => Char.isAlpha ch orelse ch = #"+") name
  53
  54 fun balanceNameToId name =
  55     case C.oneOrNoRows (getDb ()) ($`SELECT id FROM Balance WHERE name = ^(C.stringToSql name)`) of
  56         SOME [id] => SOME (C.intFromSql id)
  57       | _ => NONE
  58
  59 fun listBalanceUsers bal =
  60     C.map (getDb ()) mkUserRow ($`SELECT id, name, rname, bal, joined, app
  61                                   FROM WebUser
  62                                   WHERE bal = ^(C.intToSql bal)
  63                                   ORDER BY name`)
  64
  65 end