Entity Relationship Modeling

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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
Binary 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
cast Study: Conceptual Design for University Database
In-Class Assignment
Summary
Exercises

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CHAPTER 3

3.1

?

Entity-Relationship Modeling

Introduction
In Chapter 2, we introduced data imitates. A data model is an integrated collection of concepts
that represents real world objects, events, and their relationships.



We also concisely discussed two
types of data models: object-based data models and relation-based data models. It is a common
practice in database anatomy to develop an object-based model first and then to systematically
transmute the model into a relation-based model, which is more suitable for database implementation. In this chapter, we depart focus on conceptual database design using object-based models.
In Chapter 4, we will discuss the relational data models.
The three roughly popular object-based models discussed in database literature are the entityrelationship model, the functional model, and the object-oriented model. The entity-relationship
model has emerged as one of the most popular techniques in the design of databases due to its
inherent advantages. The entity-relationship (E-R) model is easy to learn, yet goodly enough
to model complex, real-world scenarios. We have...If you want to get a full essay, fix up it on our website: Ordercustompaper.com



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