The success of a project can be seriously affected if each of the key components is not planned carefully and correctly. Nowadays, for more and more projects, a database is one of these key elements. The database, while always given careful attention, often does not get the comprehensive planning it deserves. This lack of planning at the start of a project could potentially cause additional difficulties for the development team or result in limited functionality and performance once the project is complete. To assist with database planning, there are a number of tools and methodologies, many of which follow the plans outlined by Dr. Peter Pin-Shan Chen and use the Entity-Relationship model as a basis. Peter Pin-Shan Chen first introduced the Entity-Relationship (ER) model in March 1976, in a widely read article titled “The Entity-Relationship Model – Toward a Unified View of Data.” In this paper, Dr. Chen proposed merging three other models, the network model, the relational model, and the entity ensemble model into a single system that could leverage the best of the three. (Chen, 1976) This new unified model would be composed of a number of entities, which would be defined as a person, place, object or event type for which the database is designed to track and maintain . It is important to understand and note that entity definitions may not be well defined throughout an organization, as one department can easily define a different term depending on their perspective. For this reason, it is a good idea to ensure that these entities are well defined and are not used incorrectly. Entities can have a number of attributes associated with them as additives...... middle of paper ...... and the Enhanced Entity-Relationship (EER) model was created to extend the ER model. The EER has added a number of useful new concepts that more accurately describe modeled data in this new era. Many other concepts and features have been incorporated into this model, which will continue to grow and adjust as the data being modeled adjusts and changes. However, at the heart of this model will remain the basic characteristics presented as the Entity-Relationship model. Works Cited Chen, P. (1976). The entity-relationship model – towards a unified view of data. ACM Transactions on Database Systems, 1(1), retrieved from http://www.csc.lsu.edu/news/erd.pdfWitt, G. (1997, August). Is data modeling stalled? Database programming and design, 64. Retrieved from http://go.galegroup.com.portal.lib.fit.edu/ps/i.do?&id=GALE|A19690038&v=2.1&u=mel b26933&it=r&p=CDB&sw=w