Overview of Oracle Application Architecture
Oracle applications have a three-tier architecture which comprises of a database tier which manages the oracle database and stores all the data; an Application Tier which hosts various servers, manages communication between the desktop and database tier and contains the application file system; and a client Desktop through which users access Oracle applications.
Tier does not mean a physical machine but rather is a logical grouping of services normally spread across more than one machine. Oracle applications can be installed on a single machine and all the servers can be start from that machine. Although many physical machines may be used in configuration, scalability is derived from the processing capabilities on three separate levels namely; the desktop client tier, the application tier, and the database tier.
