The arch.gif image illustrates the three tier architecture of iSQL*Plus. It shows three side-by-side areas representing the three-tier model.The left area, labelled Web Browser, contains an image of a Personal Computer or Work station, and a Personal Digital Assistant (PDA). It has a bottom label, Client tier.The middle area, labelled Application Server, shows a generic computer box representing the application server. It has a bottom label, Middle tier.The right area, labelled Oracle Database, shows a generic drum representing a database or database server. It has a bottom label, Database tier.

Lines, labelled HTTP TCP/IP, link the web browsers in the client tier area to the Application Server in the middle tier area.

A line, labelled Oracle Net, links the Application Server in the middle tier area to the Oracle Database in the Database tier area.