Chapter 2 DATABASE DESIGN FOR SQL SERVER 2000
Chapter 2 DATABASE DESIGN FOR SQL SERVER 2000 75 REVIEW BREAK design that will improve efficiency of the data store. Data Modeling Overview We have completed our look at the basic elements of data modeling using the Entity Relationship approach. A general listing of attributes for each entity and the relationships between these entities is an important springboard for progressing through the database design to the eventual completed system. Entities can correspond with each other in several different manners. If you look at a typical sales problem, it is easy to see some of these relationships. A salesman will have many customers, a customer will have many invoices, and an invoice will have many purchased products. The most common relationship is one-to-many, but the entire database system is sure to reveal a few many-to-many relationships as well. In the sales case, for example, many salesmen sell many products. Although you now have a general listing of entities, relationships, and attributes, the logical design is not yet complete. Next you need to fine-tune the model with a process called normalization. UNDERSTANDING DATABASE NORMALIZATION . Define entities. Considering normalization and denormalization. Specify degree of normalization. Normalization in general refers to how you implement and store data. (Normalization is a design process intended to eliminate duplicate data, it is not how you implement.) In a normalized entity, the redundant data is removed and the entity is simplified to its most basic form. This usually leads to a more involved entity structure with more entities. In the same way, database normalization and
For high quality website hosting services please check cheap web hosting website.