Logical vs. Physical Modeling{2}


by Kevin Q
My article was on the differences of logical database modeling versus physical database modeling. It begins by briefly describing the two before jumping into full detail of each individually. For logical modeling it’s mostly what we have learned in class already. It’s gathering the requirements, entities, relationships and conveying them into a model. The deliverables that come from Logical Modeling are Entity relationship diagrams, Business process diagrams, and User feedback documentation. We are already familiar with ERDs through class, but the business process diagrams are models that show how parent and child processes are handled in a company or organization. To see how the company and its employees move data will help in the design of the database application interface. Physical Modeling is taking the logical modeling that has been developed and implementing it into an actual database. In the pyhsical model, tables and columns are created based on the logical model(ERD), which means entities, their attributes, relationships, primary keys, foreign keys and constraints. Everything carries over to create the physical model which can be used to view data in many ways that would be useful to employees and the company. Physical modeling is specific to the database software that is used. The deliverables in physical modeling are Server Model Diagrams and User feedback. Server model diagrams are tables, columns, and relationships within a database.

Although this article is somewhat redundant to our class learning, I found it helpful to get a brief overview of the two models(physical and logical). We cover things in much greater detail in class but its always nice to get another perspective or a brief summary of the difference between the two models and how the Logical transfers to the Physical.

Source: Stephens, Ryan K. & Plew , Ronald R. “Logical Versus Physical Database Modeling.” Database Design. Sams Publishing. March 2001. Found at developer.com “http://www.developer.com/tech/article.php/641521/Logical-Versus-Physical-Database-Modeling.htm”