Database Modeling & Design Fourth Edition- P42: Database technology has evolved rapidly in the three decades since the rise and eventual dominance of relational database systems. While many specialized database systems (object-oriented, spatial, multimedia, etc.) have found substantial user communities in the science and engineering fields, relational systems remain the dominant database technology for business enterprises. | 192 CHAPTER 9 CASE Tools for Logical Database Design The low-end tools selling for less than US 100 or available as open source provide the most basic functionality for ER modeling. The higher end products provide the kinds of support needed for serious project design such as Complete round trip engineering UML design Schema evolution change management Reverse engineering of existing systems Team support allowing multiple people to work on the same project concurrently Integration with Eclipse and .NET and other tooling products Component and convention reuse being able to reuse naming standard domain and logical models over multiple design projects Reusable assets . extensibility template Reporting The Basics All of the products in question provide strong easy to use functions for both data modeling and database design. All of these products provide the ability to graphically represent ER relationships. These tools also provide transformation processes to map from an ER model into an SQL design DDL using the transformation types described earlier in Chapter 5 Transform each entity into a table containing the key and nonkey attributes of the entity Transform every many-to-many binary or binary recursive relationship into a relationship table with the keys of the entities and the attributes of the relationship Transform every ternary or higher-level -ary relationship into a relationship table Similarly these tools produce the transformation table types described in Chapter 5 The Basics 193 An entity table with the same information content as the original entity An entity table with the embedded foreign key of the parent entity A relationship table with the foreign keys of all the entities in the relationship Chapter 5 also described rules for null transformations that must apply and the CASE tools typically enforce these. These CASE tools also help with the modeling of normal forms and denormalization to develop a true physical schema for your database as
