Transcript Business Properties and Information Technology

Chapter 3
Database
Management
Systems
PowerPoint Presentation
by Charlie Cook
Copyright © 2004 South-Western.
All rights reserved.
Learning Objectives
• To describe and analyze major approaches used to
process data related to business events
• To describe major business events in merchandising,
service and manufacturing firms
• To explain complexities and limitations of using
traditional data management approaches
• To recognize the advantages of using the database
approach to data management
• To be able to perform basic processes involved in
database design and implementation
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3–2
Overview of Order-to-Sales Process for
a Merchandising or Manufacturing Firm
FIGURE 3.1
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3–3
Overview of Order-to-Sales Process for a Service Firm
FIGURE 3.2
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3–4
Event-Driven Approach
• Raw data is captured as events occur.
• Minimum data to be collected/stored:
 Who
 What
 Where
 When
• Data can be aggregated to meet user
requirements.
homework
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3–5
Managing Data Files
• Character
 A basic unit of data (e.g., number)
• Field
 A collection of related characters (e.g., customer
name)
• Record
 A collection of related data fields
• File
 A collection of related records
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3–6
Data Maintenance: Add Customer Record
FIGURE 3.3a
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3–7
Data Maintenance: Add
Customer Record (cont’d)
FIGURE 3.3b
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3–8
Business Event Data
Processing: Enter
Customer Order
FIGURE 3.4
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3–9
Applications-based File Approach to Data Management
FIGURE 3.5a
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3–10
Database Approach to Data Management
FIGURE 3.5b
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3–11
Record Layouts Under an Applications Approach to Data Management
FIGURE 3.6
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3–12
The Database Approach
• Decouples data from applications such that data
are independent.
• Database is shared by applications.
• Data can be easily accessed by report
generators.
• Query programs must use a database
management system (DBMS) and the operating
system (OS).
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3–13
Database Management Systems (DBMS)
• A set of integrated programs designed to
simplify the tasks of creating, accessing, and
managing a database.
• DBMS functions:
 Defining the data.
 Defining the relationships among data (e.g., whether
the data structure is relational or object-oriented).
 Interfacing with the operating system
 Mapping each user’s view of the data (through
subschema to schema).
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3–14
Database Management Systems (DBMS)
(cont’d)
• Schema
 A description of the configuration of record types and
data items and the relationships among them.
 Defines the logical structure of the database.
 Defines the organizational view of the data.
• Subschema
 A description of a portion of a schema.
 DBMS map each user’s view of the data from
subschemas to the schema.
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3–15
Schemas and Subschemas
TI 3.1
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3–16
Record Layouts as Tables
FIGURE 3.7a
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3–17
Record Layouts as Tables (cont’d)
FIGURE 3.7b
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3–18
Advantages of the Database Approach
• Nonredundant data
• Ease of maintenance
• Reduced storage costs
• Data integrity
• Data independence: shareability/flexibility
• Privacy/security
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3–19
Attribute Hierarchy for the Entity CLIENT
FIGURE 3.8
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3–20
Developing Model Representations for
Entities and Attributes
FIGURE 3.9a
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3–21
Developing Model Representations for
Entities and Attributes (cont’d)
FIGURE 3.9b
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3–22
Relationships
• Strategy for identifying entity relationships
affecting the logical design of a database
 Consider existing and desired information
requirements of users
 Evaluate entity pairs to improve attribute descriptions
of entities
 Evaluate each entity to identify recursive relationships
among entities
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3–23
Object-Oriented Database Model
TI 3.3
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3–24
Example of a Relation (EMPLOYEE) and Its Parts
FIGURE 3.10
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3–25
Modeling Relationship Types
FIGURE 3.11
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3–26
Constraints on Data Model Relationships
FIGURE 3.12
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3–27
FIGURE 3.13
An Integrated Model for
the Billing and Human
Resources Processes
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3–28
Schema for the Billing and Human Resources
Portion of the Database
FIGURE 3.14
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3–29
Referential Constraints for the Relational Schema
FIGURE 3.15
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3–30
Linking Two Relations in a Many-to-Many Relationship
FIGURE 3.16
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3–31
Implementation of the Relational Schema
FIGURE 3.17a
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3–32
Implementation of the Relational Schema (cont’d)
FIGURE 3.17b
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3–33
Entity-Relationship (E-R) Diagram for
Discussion Questions 3-3, 3-4, and 3-5
FIGURE 3.18
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3–34
Relational Database for Discussion Question 3-4
and Problems 3-4 and 3-5
FIGURE 3.19
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3–35
Relational Database for Discussion Question 3-4
and Problems 3-4 and 3-5 (cont’d)
FIGURE 3.19
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3–36