scalable and flexible n-tier architecture

web application   • • • • wfmSite.aspx wfmCustomer.aspx wfmEmployee.aspx wfmReportViewer.axpx     smart client (win32)   • • • • • frmAddCustomer.vb frmCreateOrder.vb frmAddProductOrder.vb frmCreateConnection.vb frmAddPayment.vb     web server works independently unaware of the data access objects or database – it only knows the business objects ‘Published API’ (web services)		data access objects   • • • • • • • cCustomer cOrder cPayment cProduct cStockLevel cCommision cUser   business objects (service layer)   • • • • • • • cCustomer cOrder cPayment cProduct cStockLevel cCommision cUser   business components provide coarse-grained services to internal and external clients responsible for business processes       public API		database   • • • • • • • tblCustomer tblOrder tblPayment tblProduct tblStockLevel tblCommision tblUser