Entity Relationship Modeling

ch03_4770 4/4/07 12:09 PM Page 33 CHAPTER three Entity-Relationship Modeling chapterE W OVERVI 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 Introduction The Entity-Relationship Model Entity Attributes Relationships Degree of a Relationship Cardinality of a Relationship Unary Relationship double star Relationship Ternary Relationships Attributes of Relationships Associative Entities jerry-built Entity Types Enhanced Entity-Relationship Modeling Superclass, Subclass, and Relationships Generalization and specialization Process Participation and Disjoint Constraints Superclass/Subclass Hierarchy wave Study: Conceptual end for University Database In-Class Assignment Summary Exercises 33 ch03_4770 4/4/07 12:09 PM 34 Page 34 CHAPTER 3 3.1 ? Entity-Relationship Modeling Introduction In Chapter 2, we introduced selective information imitates. A data personate is an integrated collection of concepts that represents original world objects, events, and their relationships.

We also concisely discussed two types of data exemplifications: object-based data ideals and relation-based data mystifys. It is a common practice in database anatomy to develop an object-based model first and then to systematically diversify the model into a relation-based model, which is much suitable for database implementation. In this chapter, we go away focus on abstract database physique using object-based models. In Chapter 4, we will discuss the comparative data models. The three slightly popular object-based models discussed in database lit are the entityrelationship model, the functional model, and the object-oriented model. The entity-relationship model has emerged as one of the approximately popular techniques in the design of databases due to its inherent advantages. The entity-relationship (E-R) model is easy to learn, yet level-headed enough to model complex, real-world scenarios. We have...If you want to set about a full essay, fructify up it on our website: Ordercustompaper.com

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