//set deployment periods
        protected void Set_current_deployment_periods()
        {
            DataTable dt = Guard_deployment.Select_active_deployment_period("select_active_deployment_period");

            if (dt.Rows.Count > 0)
            {
                DataRow dtRow = dt.Rows[0];
                SystemConst._active_deployment_id  = Convert.ToInt32(dtRow["deploy_id"].ToString()).ToString();
                SystemConst._deployment_start_date = Convert.ToDateTime(dtRow["deploy_start_date"]);
                SystemConst._deployment_end_date   = Convert.ToDateTime(dtRow["deploy_end_date"]);
            }
        }