A database server provides the data requested by an application server on behalf of a
client. The database server does all of the remaining query processing.

The Oracle database server can audit operations performed by the application server
on behalf of individual clients as well as operations performed by the application
server on its own behalf. For example, a client operation can be a request for
information to be displayed on the client, whereas an application server operation can
be a request for a connection to the database server.

数据库服务器
数据库服务器的作用是执行应用服务器为用户提交的数据请求