public string Execute(string itemID, string srlnCode)
			{
				string retVal = String.Empty;

				var qry = new SelectQuery();
				var srln = FromTerm.Table("GXSERIALNUMBER", "srnl");
				qry.FromClause.BaseTable =srln;
				qry.Columns.Add(new SelectColumn("GXID", srln));
				qry.WherePhrase.Terms.Add(WhereTerm.CreateCompare(
					SqlExpression.Field("GXITEMID", srln), 
					SqlExpression.Parameter("@itemID"),
					CompareOperator.Equal));
				qry.WherePhrase.Terms.Add(WhereTerm.CreateCompare(
					SqlExpression.Field("GXCODE"), 
					SqlExpression.Parameter("@srlnCode"),
					CompareOperator.Equal));

				var dataAccess = AppContext.ServiceLocator.GetService<IslDataAccessDbProvider>();
				string sqlText = slRendererFactory.GetRenderer(dataAccess.Info.DBProviderName).RenderSelect(qry);
				slQueryParameters qryParams = new slQueryParameters();

				qryParams.Add("@itemID", itemID);
				qryParams.Add("@srlnCode", srlnCode);

				object res = dataAccess.ExecuteScalar(sqlText, qryParams);
				if (res != null && res != DBNull.Value)
					retVal = Convert.ToString(res);
				
				return retVal;
			}
        // Helper
        private string GetMembID(string custID)
        {
            string retVal = string.Empty;
            string sql = @"SELECT MEMB.CMID 
                        FROM CMMEMBERSHIPS MEMB
                        INNER JOIN CMCONTACTS CONT ON MEMB.CMISSUEDFORCONTACTID = CONT.CMID
                        INNER JOIN GXTRADER TRDR ON CONT.CMERPLINKID = TRDR.GXID 
                        INNER JOIN GXCUSTOMER CUST ON TRDR.GXID = CUST.GXTRDRID
                        WHERE CUST.GXID = @CUSTID";

            var prx = _appContext.ServiceLocator.GetService<IslObjectProxyActivator>();
            using (var db = prx.GetObjectProxy<IslDataAccessProxy>("Sand:DataAccessProxy", false))
            {
                var prm = new slQueryParameters("@CUSTID", custID);
                object res = db.ExecuteScalar(sql, prm);
                if (res != null && res != DBNull.Value)
                    retVal = Convert.ToString(res);
            }

            return retVal;
        }