findByIsbn :: String -> Connection -> IO (Maybe [Book])
findByIsbn s = handleViolations $ select "SELECT * FROM books WHERE isbn = ?" s
findByIsbn :: String -> Connection -> IO (Maybe [Book])
findByIsbn s = handleViolations $ select "SELECT * FROM books WHERE isbn = ?" s
findByIsbn s = handleViolations $ select "SELECT * FROM books WHERE isbn = ?" s