Systems Analysis and Design Tutorial
Sometimes there is a need to tightly integrate two or more application systems. Integration can occur at the database level or at the functional level.
The following diagram depicts two application systems, each designed for different user groups using different architectures can integrate by sharing a common database.
Application systems can also be integrated at the business logic level. For example, a "self serve" Internet application that is used by end customers could share a business logic component that is used by a client server application that is used by staff in a call centre.
Should the common component be upgraded at some point, the upgrade is reflected consistency in both application systems.
Although it is feasible for application systems built on the same platform using the same technologies to share common components, it is often not feasible for applications that use different technologies to easily communicate.