ch03_4770 4/4/07 12:09 PM Page 33 CHAPTER three Entity- family 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 entryway The Entity-Relationship Model Entity Attributes Relationships breaker point of a Relationship Cardinality of a Relationship Unary Relationship Binary Relationship Ternary Relationships Attributes of Relationships Associative Entities jerry-built Entity Types deepen Entity-Relationship Modeling Superclass, Subclass, and Relationships Generalization and Specialization Process Participation and disjoin Constraints Superclass/Subclass Hierarchy cast Study: Conceptual Design for University Database In-Class identification 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 entropy imitates. A data model is an combine collection of concepts that represents real world objects, events, and their relationships.
We also concisely discussed dickens types of data models: object-based data models and relation-based data models. It is a common make in database anatomy to develop an object-based model first and whence to systematically transmute the model into a relation-based model, which is more capable for database implementation. In this chapter, we depart focus on conceptual database founding using object-based models. In Chapter 4, we will discuss the relational data models. The three rough ly customary 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 well-fixed to learn, yet goodly enough to model complex, real-world scenarios. We have...If you want to cast down a full essay, fix up it on our website: OrderCustomPaper.com
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