Four ways to integrate

Enterprise application integration is not a one-dimensional concept but

involves a number of different approaches. In his analysis of EAI, Mike

Gilpin, vice president and research leader with Giga Information Group,

identified four levels of integration:

* Data integration includes several options. Different applications

could share access to a single database or maintain separate databases with

connections among them. The derived database or data warehouse allows for

periodic data access and analysis. Finally, there is the virtual database

in which an application is written to access a program that can retrieve

information from where it physically resides and aggregate it in the end

user's system memory.

* Business logic integration links programs together with interfaces

or adapters that can send or receive messages upon an end user's request.

* Interaction level integration ties together user interfaces, such

as desktop computers, Web portals or call centers.

* Business process integration codifies a procedure that would occur

under specific circumstances across different systems. For example, if someone's

visa expires, there could be a procedure in place in which the Immigration

and Naturalization Service automatically informs FBI officials, who may

also contact the CIA.