ARCHITECTURE
One of the key features of the
exprimer architecture is the use of abstraction to keep the three layers independent
of each other:
The Data Layer
The details of the databases (location and particular database
technology) and their schemas are captured in XML form in
a Mapping Entity and are not exposed to developers or to
the client application.
The Business Layer
The addition of databases or changes to database properties
are not reflected in the Business Layer, only in the Mapping
Entity. The Business Layer presents a uniform ISO 23950
interface to the different client technologies. These interact
with the Business Layer using XML-based ISO-standard queries.
The Presentation Layer
The architecture supports multiple client technologies,
including Java, HTML and WML.
Each client technology is independent of the middle layer
and auto-configures using an XML Profile, which is independent
of the client technologies. The Profile also determines
the security permissions for the user, and how search results
are presented.
Next: Search & Update Engines:
