chapter2 part1

chapter2 part1 - Outline Chapter 2 Data modeling Their...

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1 Chapter 2 Data Models part 1 BUS 173 Winter 2011 Dr. Hamouda 2 Outline Data modeling Their importance Basic data-modeling building blocks Business rules They influence on database design History of data models Classification of data models based on their level of abstraction 3 Introduction Designers, programmers, and end users see data in different ways Diverse groups of users Difficult to obtain acceptance of a common vocabulary Different views of same data lead to designs that do not reflect organization’s operation Marketing Customer buying habit Customer buying motivation call planning Accounting Assets Liabilities ledgers Production Inventory Lead time Customer order 4 Introduction Compromise to find least objectionable solution Unify organization by establishing a common vocabulary This is achieved through data abstraction and modeling Data modeling reduces complexities of database design Various degrees of data abstraction help reconcile varying views of same data 5 Data Modeling and Data Models Data models (blueprint) Relatively simple representations of complex real-world data structures Often graphical Model: an abstraction of a real-world object or event Useful in understanding complexities of the real-world environment Data modeling is iterative and progressive 6 Data Model A data model should contain the following components: A description of the data structure that will store the end-user data A set of enforceable rules to guarantee the integrity of the data A data manipulation methodology to support the real world data transformation
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7 Data Model Basic Building Blocks Entity : anything (a topic of interest or an item in the real world) about which data are to be collected and stored Attribute : a characteristic of an entity Relationship : describes an association among entities One-to-many (1:M) relationship Many-to-many (M:N or M:M) relationship One-to-one (1:1) relationship Constraint : a restriction placed on the data 8 Example: University Database University Database Registration Grade Recording Faculty Assignment Course Scheduling Entities : students, faculty, courses, offerings, enrollments Relationships : faculty teach offerings, students enroll in offerings, offerings made of courses, . .. 9
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This note was uploaded on 07/27/2011 for the course BUS 173 taught by Professor Essiahamouda during the Winter '11 term at UC Riverside.

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chapter2 part1 - Outline Chapter 2 Data modeling Their...

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