A
client-server computer network application is one in which a client,
thin client or
fat client[?], which instantiates the
user interface of the application, connects with an
application server or
database system. When a client
connects directly to a database system, or to a monolithic application server, the architecture of the application
is a 2-tier architecture. In recent years, it is more common for a thin client which does not incorporate
business logic, but only user interface elements to connect to an application server that implements
the business logic, and which transitively
(i.e. in turn) communicates with a database server, which stores the raw data used by the application. Such
an architecture is called a 3-tier architecture, which is a special case of n-tier architecture.
In general, n-tier architectures may employ a number of distinct services, including transitive relations
between application servers implementing different functions of business logic, each of which may
or may not employ a distinct or shared database system.
Also see
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