public DataTable RetExecucao()
        {
            DataTable dt = null;

            try
            {
                con.Conectar();
                string query = "SELECT * FROM execucao";
                dt = con.RetDataTable(query);
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }
            finally
            {
                con.Desconectar();
            }
            return(dt);
        }