Systems Analysis and Design Tutorial
There is sometimes 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. The applications have different architectures but 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 customers could share a business logic component that is used by staff in a call centre. That system could be a client server application.
Should the common component be upgraded at some point, both application systems would benefit from the upgrade.