PowerPoint Presentation by Charlie Cook Copyright © 2004 South-Western. All rights reserved. Chapter 3 Database Management Systems Database Management Systems

Copyright © 2004 South-Western. All rights reserved.3–2 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

Copyright © 2004 South-Western. All rights reserved.3–3 Overview of Order-to-Sales Process for a Merchandising or Manufacturing Firm FIGURE 3.1

Copyright © 2004 South-Western. All rights reserved.3–4 Overview of Order-to-Sales Process for a Service Firm FIGURE 3.2

Copyright © 2004 South-Western. All rights reserved.3–5 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

Copyright © 2004 South-Western. All rights reserved.3–6 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

Copyright © 2004 South-Western. All rights reserved.3–7 Data Maintenance: Add Customer Record FIGURE 3.3a

Copyright © 2004 South-Western. All rights reserved.3–8 Data Maintenance: Add Customer Record (cont’d) FIGURE 3.3b

Copyright © 2004 South-Western. All rights reserved.3–9 Business Event Data Processing: Enter Customer Order FIGURE 3.4

Copyright © 2004 South-Western. All rights reserved.3–10 Applications-based File Approach to Data Management FIGURE 3.5a

Copyright © 2004 South-Western. All rights reserved.3–11 Database Approach to Data Management FIGURE 3.5b

Copyright © 2004 South-Western. All rights reserved.3–12 Record Layouts Under an Applications Approach to Data Management FIGURE 3.6

Copyright © 2004 South-Western. All rights reserved.3–13 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).

Copyright © 2004 South-Western. All rights reserved.3–14 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).

Copyright © 2004 South-Western. All rights reserved.3–15 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.

Copyright © 2004 South-Western. All rights reserved.3–16 Schemas and Subschemas TI 3.1

Copyright © 2004 South-Western. All rights reserved.3–17 Record Layouts as Tables FIGURE 3.7a

Copyright © 2004 South-Western. All rights reserved.3–18 Record Layouts as Tables (cont’d) FIGURE 3.7b

Copyright © 2004 South-Western. All rights reserved.3–19 Advantages of the Database Approach Nonredundant data Ease of maintenance Reduced storage costs Data integrity Data independence: shareability/flexibility Privacy/security

Copyright © 2004 South-Western. All rights reserved.3–20 Attribute Hierarchy for the Entity CLIENT FIGURE 3.8

Copyright © 2004 South-Western. All rights reserved.3–21 Developing Model Representations for Entities and Attributes FIGURE 3.9a

Copyright © 2004 South-Western. All rights reserved.3–22 Developing Model Representations for Entities and Attributes (cont’d) FIGURE 3.9b

Copyright © 2004 South-Western. All rights reserved.3–23 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

Copyright © 2004 South-Western. All rights reserved.3–24 Object-Oriented Database Model TI 3.3

Copyright © 2004 South-Western. All rights reserved.3–25 Example of a Relation (EMPLOYEE) and Its Parts FIGURE 3.10

Copyright © 2004 South-Western. All rights reserved.3–26 Modeling Relationship Types FIGURE 3.11

Copyright © 2004 South-Western. All rights reserved.3–27 Constraints on Data Model Relationships FIGURE 3.12

Copyright © 2004 South-Western. All rights reserved.3–28 An Integrated Model for the Billing and Human Resources Processes FIGURE 3.13

Copyright © 2004 South-Western. All rights reserved.3–29 Schema for the Billing and Human Resources Portion of the Database FIGURE 3.14

Copyright © 2004 South-Western. All rights reserved.3–30 Referential Constraints for the Relational Schema FIGURE 3.15

Copyright © 2004 South-Western. All rights reserved.3–31 Linking Two Relations in a Many-to-Many Relationship FIGURE 3.16

Copyright © 2004 South-Western. All rights reserved.3–32 Implementation of the Relational Schema FIGURE 3.17a

Copyright © 2004 South-Western. All rights reserved.3–33 Implementation of the Relational Schema (cont’d) FIGURE 3.17b

Copyright © 2004 South-Western. All rights reserved.3–34 Entity-Relationship (E-R) Diagram for Discussion Questions 3-3, 3-4, and 3-5 FIGURE 3.18

Copyright © 2004 South-Western. All rights reserved.3–35 Relational Database for Discussion Question 3-4 and Problems 3-4 and 3-5 FIGURE 3.19

Copyright © 2004 South-Western. All rights reserved.3–36 Relational Database for Discussion Question 3-4 and Problems 3-4 and 3-5 (cont’d) FIGURE 3.19