addBook
  :: String -> String -> String
  -> Connection
  -> IO (Maybe Int64)
addBook isbn_ title_ auth = handleViolations $ \cn ->
  execute cn templ (isbn_, title_, auth)
    where templ = "INSERT INTO books (isbn, title, author, owned, available)\
                  \ VALUES ( ?, ?, ?, 0, 0 )"
addBook
  :: String -> String -> String
  -> Connection
  -> IO (Maybe Int64)
addBook isbn_ title_ auth = handleViolations $ \cn ->
  execute cn templ (isbn_, title_, auth)
    where templ = "INSERT INTO books (isbn, title, author, owned, available)\
                  \ VALUES ( ?, ?, ?, 0, 0 )"
addBook isbn_ title_ auth = handleViolations $ \cn ->
  execute cn templ (isbn_, title_, auth)
    where templ = "INSERT INTO books (isbn, title, author, owned, available)\
                  \ VALUES ( ?, ?, ?, 0, 0 )"