1. The Presentation Level (view 1, ...view n) is created using a Graphical User Interface (GUI) tools such as Visual Basic, Oracle Forms, PowerBuilder etc. This level is for end users, e.g. clerks, sales personnel etc.

2. The Conceptual Level is an abstraction, which hides the details of physical storage. This level is for programmers and database administrators, like us.

3. The physical level is physical storage structure and access paths. The mapping between the conceptual level and physical level is handled by the database management system (DBMS).

The DBMS with the largest market share, at this time, is Oracle. The other popular multi-user DBMSs are DB2 from IBM, Sybase, SQL Server from Microsoft, and Informix.

Return to DatabaseConcepts, Syllabus, Menu