public boolean executeUpdate(String sql)
    {
        Statement st;
        try
        {
            Log.logi("Start execution.");
            st = connection.createStatement();
            st.executeUpdate(sql);
            st.close();
            Log.logi("End execution.");
            return true;

        } catch (SQLException ex)
        {
            Log.loge(ex.getMessage());
        }

        return false;
    }