A Logical View is concerned with what do these 'things' represent; a Physical View is concerned with how these 'things' are realized.
A Logical View is a view as presented to the end user. A Physical View is a technical description of the implementation of the Logical View: A Logical View is as the customers or users see and understand it, and should be used to communicate with them. A Physical View is how and where the information resides. System development staff should:
(a) communicate with actors in logical view and terms, and
(b) translate agreed/approved logical view or changes to physical view correctly.
(a) communicate with actors in logical view and terms, and
(b) translate agreed/approved logical view or changes to physical view correctly.
A Logical View focuses on functional requirements or data modeling. A Physical View does need to address quality requirements like resilience and availability: That is another difference between the two. From Database Management perspective, the Logical view is at entity and field level, including the kind of data (date, text, number). Natural keys are defined, and where not possible, artificial keys. Relationships include cardinality. Data quality elements are introduced as well, so some rules around when relationships are valid, or what states of entities are valid, are also included. A Physical View is at entity and fields, including physical data types like VarChar. This will also include M->M relationship tables, index optimization, materialized views, etc. It may be denormalized to support performance as well. it may include database-specific entities used to protect data quality.
A Logical View is concerned with the semantics of the elements, what do these 'things' represent; a Physical View is concerned with both the semantics and syntax of the elements on how these 'things' are realized.
4 comments:
Thank you for the details.
Your explanation of both logical and physical views are really clear. As I may suppose this structure may be applied to virtual data rooms described on virtual data room reviews.
A Virtual Data Room (VDR) is a progression of exclusive extranets that give an online store of information. Organizations normally utilize a safe virtual information space to impart basic data to outer clients and accomplices in a protected, online condition. The virtual deal room empowers gatherings to see reports pertinent to a specific exchange for approved clients. Reports are put away in electronic arrangement on a focal server and got to through the Internet.
This is, by far, the best, most concise description of the differences between LDM and PDM that I've encountered. Thanks for your post.
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