{-------------------------------------------------------------------------------------
-
- HDBC connectivity
- Programmer: Leonidas Fegaras
- Email: fegaras@cse.uta.edu
- Web: http://lambda.uta.edu/
- Creation: 05/12/08, last update: 05/12/08
- 
- Copyright (c) 2008 by Leonidas Fegaras, the University of Texas at Arlington. All rights reserved.
- This material is provided as is, with absolutely no warranty expressed or implied.
- Any use is at your own risk. Permission is hereby granted to use or copy this program
- for any purpose, provided the above notices are retained on all copies.
-
--------------------------------------------------------------------------------------}


module XML.HXQ.DB where

import Database.HDBC
import XML.HXQ.XTree


sql2xml :: SqlValue -> XTree
sql2xml value =
    case value of
      SqlString s -> XText s
      SqlByteString bs -> XText (show bs)
      SqlWord32 n -> XInt (fromEnum n)
      SqlWord64 n -> XInt (fromEnum n)
      SqlInt32 n -> XText (show n)
      SqlInt64 n -> XText (show n)
      SqlInteger n -> XInt (fromEnum n)
      SqlChar c -> XText [c]
      SqlBool b -> XBool b
      SqlDouble n -> XText (show n)
      SqlRational n -> XText (show n)
      SqlEpochTime n -> XText (show n)
      SqlTimeDiff n -> XText (show n)
      SqlNull -> XText ""


xml2sql :: XTree -> SqlValue
xml2sql e =
    case e of
      XText s -> SqlString s
      XInt n -> SqlInteger (toInteger n)
      XFloat n -> SqlString (show n)
      XBool n -> SqlBool n


executeSQL :: Statement -> XSeq -> IO XSeq
executeSQL stmt args
    = do n <- handleSqlError (execute stmt (map xml2sql args))
         result <- handleSqlError (fetchAllRowsAL stmt)
         return (map (\x -> XElem "row" [] 0 (map (\(s,v) -> XElem s [] 0 [sql2xml v]) x)) result)


prepareSQL :: (IConnection conn) => conn -> String -> IO Statement
prepareSQL db sql = handleSqlError (prepare db sql)