public InvoiceTableCollection FetchAll()
 {
     InvoiceTableCollection coll = new InvoiceTableCollection();
     Query qry = new Query(InvoiceTable.Schema);
     coll.LoadAndCloseReader(qry.ExecuteReader());
     return coll;
 }
 public InvoiceTableCollection FetchByQuery(Query qry)
 {
     InvoiceTableCollection coll = new InvoiceTableCollection();
     coll.LoadAndCloseReader(qry.ExecuteReader()); 
     return coll;
 }
 public InvoiceTableCollection FetchByID(object InvoiceNumber)
 {
     InvoiceTableCollection coll = new InvoiceTableCollection().Where("InvoiceNumber", InvoiceNumber).Load();
     return coll;
 }