Database Systems
Design, Implementation, and Management
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Chapter 2
Data Models
©2015 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Learning Objectives
In this chapter we will discuss data models.
Why data models are important
The basic data-modeling building blocks
What business rules are and how they influence
database design
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©2015 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Modeling and Data Models
Database design focuses on how the database
structure will be used to store and manage end–user
data.
Data modeling is the first step in designing a database
and refers to the process of creating a specific data
model for a determined problem domain.
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©2015 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Modeling and Data Models
Model – Abstraction of a real-world object or event
Data models: Simple graphical representations of
complex real-world data structures
Data modeling: Iterative and progressive process of
creating a specific data model for a determined
problem domain
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©2015 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Modeling and Data Models
Traditionally, database designers relied on good
judgment to help them develop a good data model.
If each of the students in this class has to create a data
model for a video store, it’s very likely that each of
them will come up with a different model.
Which one would be the correct one?
The simple answer is “the one that meets all the end–
user requirements”
Importance of correctly documenting business rules
through requirements gathering!
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©2015 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
Importance of Data Models
Are a communication tool
Give an overall view of the database
Organize data for various users
Are an abstraction for the creation of good
database
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Data Model Basic Building Blocks
Entity: Unique and distinct object used to collect
and store data
Attribute: Characteristic of an entity
Relationship: Describes an association among
