External schema

An External schema (also called view schema) is created with the intention to deal with how the end users of a system "view" the data. Thus "external" is differentiated here from the conceptual and internal schemas. This is inline with the Three schema approach which is also applied in the [Three tier architecture and a proven and widespread way of designing systems. In the following diagram depicting a multitier-architecture. The external schema would be adapted to the Clients, the conceptual schema to the business/application logic and the internal schema to the database.