Tuesday, August 31, 2010

External, Logical and Internal view

A database management system provides the ability for many different users to share data and process resources. But as there can be many different users, there are many different database needs. The question now is: How can a single, unified database meet the differing requirement of so many users?

A DBMS minimizes these problems by providing two views of the database data: an external view(or User view), logical view(or conceptual view)and physical(or internal) view. The user’s view, of a database program represents data in a format that is meaningful to a user and to the software programs that process those data.

One strength of a DBMS is that while there is typically only one conceptual (or logical) and physical (or Internal) view of the data, there can be an endless number of different External views. This feature allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. Thus the logical view refers to the way user views data, and the physical view to the way the data are physically stored and processed.

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