arch.gif illustrates the description given in the preceeding paragraphs under the heading Three Tier Architecture.
The illustration shows three side-by-side areas representing the three-tier model.
The left area contains an image of a Personal Computer or Work station. It has a top label of Client Tier and an inside label of iSQL*Plus User Interface.
The middle area shows a generic computer box representing the web server. It has a top label of Oracle HTTP Server and inside labels of iSQL*Plus Server and Oracle Net.
The right area shows a generic computer box representing the database server with a linked drum representing a database. It has a top label of Database Server and inside labels of RDBMS and Oracle Net.
The left area, the iSQL*Plus User Interface, is connected to the middle area, the Oracle HTTP Server, by a bidirectional arrow labeled on top with TCP/IP Network, and labeled underneath with HTTP Protocol.
The middle area, the Oracle HTTP Server, is connected to the right area, the Oracle database, by a bidirectional arrow labeled Oracle Net.