Logical vs. Physical Modeling{3}


The two authors of this article start off by declaring that data modeling serves as a link between business needs and system requirements. They stress that if we are going to work with databases, it is important to understand the difference between logical and physical modeling, and how they relate to each other. First, Logical Modeling deals with gathering business requirements and converting those requirements into a model. Also, it involves gathering information about business processes, business entities, and organizational units. After, diagrams and reports are produced (entity relationship , business process, and process flow diagrams). According to the authors, it’s important to note that logical modeling affects the direction of database design and indirectly affects the performance and administration of an implemented database. More options become available when time is invested performing logical modeling. Next, the authors go into Physical modeling. Physical modeling involves the actual design of the database according to the requirements that were established during logical modeling. Physical modeling deals with the conversion of the logical, or business model, into a relational database model. During physical modeling, objects are created based on everything that was defined during logical modeling. Other objects like indexes and snapshots can be defined during physical modeling. Physical modeling is when all the pieces come together to complete the process of defining a database for a business. The authors conclude that the importance of understanding the difference between logical and physical modeling helps us to build better organized and more effective database systems.

In week 4 and this past week (week 5)  we learned about both Logical and Physical Database Design. This article definitely relates to the topic for this past week. The purpose of Physical database design is to translate the logical description of data into the technical specifications for storing and retrieving data. The primary goal of physical database design is data processing efficiency.

I liked the article, but at the same time I didn’t because it didn’t go into more detail about both logical and physical database design. The article is very basic and general and is helpful to those who have no clue about database design. The textbook is much more specific, and learned more there. Regardless, I would still recommend to read this article to those that want a basic overview what the difference between logical and physical modeling are.

Ryan K. Stephens and Ronald R. Plew. (2011, March). Logical Versus Physical Database Modeling. Developer.com. Retrieved October 27, 2012, from http://www.developer.com/tech/article.php/641521/Logical-Versus-Physical-Database-Modeling.htm