2. Training on Data Modeling:
[Submitted by: Anil Khatwad, Miramar, Florida, United States.]
Even though the concept of data modeling has been around for a long time, it is still not widely practiced. The phrase data modeling is interpreted differently by different people and methodologies. The purpose of this training is to teach the importance of building a logical data model and different terminologies and symbols used in an ER diagram.
This article answers the following questions:- What is a logical data model?
- Who uses the logical data model?
- Why build one?
- How is a logical data model different than a physical data model?
- What happens if you don’t build a logical data model?
The Logical Data Model refers to a higher level of the business data. Once we know the business data requirements, we can normalize and implement the data. However, if we do not have a clear understanding of the business requirements all of the design and implementation work in the world will not result in a good quality application.
What is a logical data model?- A logical data model is a graphical representation of the information requirements of a business area; it is not a database.
- The word logical is very critical because it modifies the phrase data modeling to a more specific activity. A logical data model is independent of a physical, data storage device.
- This is the key concept of the logical data model. The reason that a logical data model must be independent of technology is simply because technology is changing so rapidly.
- The logical data model is a picture of all of the pieces of information necessary to run the business.
- The logical data model is built using an Entity Relationship Diagram (ERD) - a standard modeling technique used by data modelers around the world.
Data Architects create the logical data model. Business Area Experts describe their data requirements to the data architect and review the models created. Data Architect also works with the process analyst to link data with processes. Data Architect is responsible for getting approval of the logical data model from the Business Area Experts and then works with the DBA to transition the logical model to the physical model.
Why Build a Logical Data Model?The most important reason to build a logical data model is to confirm the users and analyst understands of the business requirements to assure that the system developed satisfies the business need.
Training on Data Modeling - Continued.....