Logical And Physical View

[sameer9 0]

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: a logical (external) view and physical (internal) view. The logical view/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. That is, the logical view tells the user, in user terms, what is in the database. The physical view deals with the actual, physical arrangement and location of data in the direct access storage devices(DASDs). Database specialists use the physical view to make efficient use of storage and processing resources. With the logical view users can see data differently from how they are stored, and they do not want to know all the technical details of physical storage. After all, a business user is primarily interested in using the information, not in how it is stored.

One strength of a DBMS is that while there is only one physical view of the data, there can be an endless number of different logical 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

Notice from Yordan:

Please do not post copied text on this forum. Posting copied text can lead to a ban.

Edited July 4, 2009 by yordan
Quoted the text copied from http://en.wikipedia.org/wiki/Database_management_system (see edit history)

[Tremayne 0]

this is interesting to read, surprised i read it all the way through actually, but why did you just post this and not any of your thoughts on it?

[yordan 10]

this is interesting to read, surprised i read it all the way through actually, but why did you just post this and not any of your thoughts on it?

I agree with tremayne. Posting parts of wikipedia articles have absolutely no interest. We are only interested by your thoughts about this. For instance do you understand the differences between physical and logical view ? For instance, are you ready to tell your boss he must buy a very expensive RDBMS manager because it is able to create a materialized view of a complex external join whereas his current database manager cannot ?

[surfermac 0]

are you a computers student????why did you post this??not interesting