inquiry by using execute query

In form level in class :-
class declaration:-

public class FormRun extends ObjectRun
{
    QueryBuildRange qbr;
}

--------------------------------------------------------------------------------------------------------------
Execute query method in data source level:-


public void executeQuery()
{
    qbr.value(PurchTable_VendGroup.valueStr());
    qbr.value(PurchTable_InvoiceAccount.valueStr());
    super();
}

-------------------------------------------------------------------------------------------------------------
Init method in datasource level:-

public void init()
{
    super();
    qbr=this.query().dataSourceName("PurchTable").addRange(fieldNum(PurchTable,VendGroup));
    qbr=this.query().dataSourceName("PurchTable").addRange(fieldNum(PurchTable,InvoiceAccount));
}

---------------------------------------------------------------------------------------------------------------
CLicked method on Button in Design level:-

void clicked()
{
    super();

    PurchTable_ds.executeQuery();

}