© 2009 Pearson Education, Inc. Publishing as Prentice Hall 1 Unit 1: Background and Terminology Chapters 1 + 2: Modern Database Management 9 th Edition Jeffrey A. Hoffer, Mary B. Prescott, Heikki Topi

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2 Definitions Database: organized collection of logically related data Database: organized collection of logically related data Data: stored representations of meaningful objects and events Data: stored representations of meaningful objects and events Structured: numbers, text, dates Structured: numbers, text, dates Unstructured: images, video, documents Unstructured: images, video, documents Information: data processed to increase knowledge in the person using the data Information: data processed to increase knowledge in the person using the data Metadata: data that describes the properties and context of user data Metadata: data that describes the properties and context of user data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 3 Figure 1-1a Data in context Context helps users understand data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4 Graphical displays turn data into useful information that managers can use for decision making and interpretation Figure 1-1b Summarized data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 5 Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and data context

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 6 Data Characteristics Status vs. Event Data Status Event = a database action (create/update/delete) that results from a transaction Figure 11-6 Example of DBMS log entry

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7 Data Characteristics Transient vs. Periodic Data With transient data, changes to existing records are written over previous records, thus destroying the previous data content Figure 11-7 Transient operational data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 8 Periodic data are never physically altered or deleted once they have been added to the store Data Characteristics Transient vs. Periodic Data Figure 11-8 Periodic warehouse data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 9 Derived Data Data that can be computed as opposed to stored facts. Data that can be computed as opposed to stored facts. Objectives Objectives Ease of use for decision support applications Ease of use for decision support applications Fast response to predefined user queries Fast response to predefined user queries Customized data for particular target audiences Customized data for particular target audiences Ad-hoc query support Ad-hoc query support Data mining capabilities Data mining capabilities

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 10 Duplicate Data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 11 Disadvantages of File Processing Program-Data Dependence Program-Data Dependence All programs maintain metadata for each file they use All programs maintain metadata for each file they use Duplication of Data Duplication of Data Different systems/programs have separate copies of the same data Different systems/programs have separate copies of the same data Limited Data Sharing Limited Data Sharing No centralized control of data No centralized control of data Lengthy Development Times Lengthy Development Times Programmers must design their own file formats Programmers must design their own file formats Excessive Program Maintenance Excessive Program Maintenance 80% of information systems budget 80% of information systems budget

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 12 Problems with Data Dependency Each application programmer must maintain his/her own data Each application programmer must maintain his/her own data Each application program needs to include code for the metadata of each file Each application program needs to include code for the metadata of each file Each application program must have its own processing routines for reading, inserting, updating, and deleting data Each application program must have its own processing routines for reading, inserting, updating, and deleting data Lack of coordination and central control Lack of coordination and central control Non-standard file formats Non-standard file formats

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 13 Problems with Data Redundancy Waste of space to have duplicate data Waste of space to have duplicate data Causes more maintenance headaches Causes more maintenance headaches The biggest problem: The biggest problem: Data changes in one file could cause inconsistencies Data changes in one file could cause inconsistencies Compromises in data integrity Compromises in data integrity

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 14 SOLUTION: The DATABASE Approach Central repository of shared data Central repository of shared data Data is managed by a controlling agent Data is managed by a controlling agent Stored in a standardized, convenient form Stored in a standardized, convenient form Requires a Database Management System (DBMS)

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 15 Database Management System DBMS manages data resources like an operating system manages hardware resources A software system that is used to create, maintain, and provide controlled access to user databases Order Filing System Invoicing System Payroll System DBMS Central database Contains employee, order, inventory, pricing, and customer data

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 16 Advantages of the Database Approach Program-data independence Program-data independence Planned data redundancy Planned data redundancy Improved data consistency Improved data consistency Improved data sharing Improved data sharing Increased application development productivity Increased application development productivity Enforcement of standards Enforcement of standards Improved data quality Improved data quality Improved data accessibility and responsiveness Improved data accessibility and responsiveness Reduced program maintenance Reduced program maintenance Improved decision support Improved decision support

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17 Costs and Risks of the Database Approach New, specialized personnel New, specialized personnel Installation and management cost and complexity Installation and management cost and complexity Conversion costs Conversion costs Need for explicit backup and recovery Need for explicit backup and recovery Organizational conflict Organizational conflict

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 18 Elements of the Database Approach Data models Data models Graphical system capturing nature and relationship of data Graphical system capturing nature and relationship of data Enterprise Data Model–high-level entities and relationships for the organization Enterprise Data Model–high-level entities and relationships for the organization Project Data Model–more detailed view, matching data structure in database or data warehouse Project Data Model–more detailed view, matching data structure in database or data warehouse Relational Databases Relational Databases Database technology involving tables (relations) representing entities and primary/foreign keys representing relationships Database technology involving tables (relations) representing entities and primary/foreign keys representing relationships Use of Internet Technology Use of Internet Technology Networks and telecommunications, distributed databases, client- server, and 3-tier architectures Networks and telecommunications, distributed databases, client- server, and 3-tier architectures Database Applications Database Applications Application programs used to perform database activities (create, read, update, and delete) for database users Application programs used to perform database activities (create, read, update, and delete) for database users

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 19 Figure 1-5 Components of the Database Environment

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 20 Components of the Database Environment CASE Tools – computer-aided software engineering CASE Tools – computer-aided software engineering Repository – centralized storehouse of metadata Repository – centralized storehouse of metadata Database Management System (DBMS) – software for managing the database Database Management System (DBMS) – software for managing the database Database – storehouse of the data Database – storehouse of the data Application Programs – software using the data Application Programs – software using the data User Interface – text and graphical displays to users User Interface – text and graphical displays to users Data/Database Administrators – personnel responsible for maintaining the database Data/Database Administrators – personnel responsible for maintaining the database System Developers – personnel responsible for designing databases and software System Developers – personnel responsible for designing databases and software End Users – people who use the applications and databases End Users – people who use the applications and databases

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 21 The Range of Database Applications Personal databases Personal databases Workgroup databases Workgroup databases Departmental/divisional databases Departmental/divisional databases Enterprise database Enterprise database Enterprise resource planning (ERP) systems Enterprise resource planning (ERP) systems Data warehousing implementations Data warehousing implementations

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 22

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 23 Figure 1-7 Workgroup database with wireless local area network

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 24 Enterprise Database Applications Enterprise Resource Planning (ERP) Enterprise Resource Planning (ERP) Integrate all enterprise functions (manufacturing, finance, sales, marketing, inventory, accounting, human resources) Integrate all enterprise functions (manufacturing, finance, sales, marketing, inventory, accounting, human resources) Data Warehouse Data Warehouse Integrated decision support system derived from various operational databases Integrated decision support system derived from various operational databases

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 25 Data Warehousing Data Warehouse: Data Warehouse: A subject-oriented, integrated, time-variant, non- updatable collection of data used in support of management decision-making processes A subject-oriented, integrated, time-variant, non- updatable collection of data used in support of management decision-making processes Subject-oriented: e.g. customers, patients, students, products Subject-oriented: e.g. customers, patients, students, products Integrated: Consistent naming conventions, formats, encoding structures; from multiple data sources Integrated: Consistent naming conventions, formats, encoding structures; from multiple data sources Time-variant: Can study trends and changes Time-variant: Can study trends and changes Non-updatable: Read-only, periodically refreshed Non-updatable: Read-only, periodically refreshed Data Mart: Data Mart: A data warehouse that is limited in scope A data warehouse that is limited in scope

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 26 Need for Data Warehousing Integrated, company-wide view of high-quality information (from disparate databases) Integrated, company-wide view of high-quality information (from disparate databases) Separation of operational and informational systems and data (for improved performance) Separation of operational and informational systems and data (for improved performance) Table 11-1 – Comparison of Operational and Informational Systems

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 27 Figure 1-8 An enterprise data warehouse

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 28 Figure 11-2 Independent data mart data warehousing architecture Data marts: Mini-warehouses, limited in scope E T L Separate ETL for each independent data mart Data access complexity due to multiple data marts

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 29 Figure 11-3 Dependent data mart with operational data store: a three-level architecture E T L Single ETL for (EDW) enterprise data warehouse (EDW) Simpler data access ODS ODS provides option for obtaining current data Dependent data marts loaded from EDW

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 30 E T L Near real-time ETL for Data Warehouse ODS data warehouse ODS and data warehouse are one and the same Data marts are NOT separate databases, but logical views of the data warehouse  Easier to create new data marts Figure 11-4 Logical data mart and real time warehouse architecture

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 31 Application Logic in C/S Systems GUI Interface Procedures, functions, programs DBMS activities Processing Logic I/O processing I/O processing Business rules Business rules Data management Data management Storage Logic Data storage/retrieval Data storage/retrieval Presentation Logic Input–keyboard/mouse Input–keyboard/mouse Output–monitor/printer Output–monitor/printer

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 32 Client/Server Architectures File Server Architecture File Server Architecture Database Server Architecture Database Server Architecture Three-tier Architecture Three-tier Architecture Client does extensive processing Client does little processing

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 33 File Server Architecture All processing is done at the PC that requested the data All processing is done at the PC that requested the data Entire files are transferred from the server to the client for processing Entire files are transferred from the server to the client for processing Problems: Problems: Huge amount of data transfer on the network Huge amount of data transfer on the network Each client must contain full DBMS Each client must contain full DBMS Heavy resource demand on clients Heavy resource demand on clients Client DBMSs must recognize shared locks, integrity checks, etc. Client DBMSs must recognize shared locks, integrity checks, etc. FAT CLIENT

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 34 Figure 9-2 File server model FAT CLIENT

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 35 Two-Tier Database Server Architectures Client is responsible for Client is responsible for I/O processing logic I/O processing logic Some business rules logic Some business rules logic Server performs all data storage and access processing Server performs all data storage and access processing  DBMS is only on server

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 36 Three-Tier Architectures Thin Client PC just for user interface and a little application processing. Limited or no data storage (sometimes no hard drive) GUI interface (I/O processing) Browser Business rules Web Server Data storage DBMS Client Application server Database server

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 37 Figure 9-4a Generic three-tier architecture Thinnest clients Business rules on separate server DBMS only on DB server

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 38

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 39 Common Logic Distributions Figure 9-5a Two-tier client- server environments Figure 9-5b n-tier client- server environment Processing logic could be at client, server, or both Processing logic will be at application server or Web server

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40 Middleware Software that allows an application to interoperate with other software Software that allows an application to interoperate with other software No need for programmer/user to understand internal processing No need for programmer/user to understand internal processing Accomplished via Application Program Interface (API) Accomplished via Application Program Interface (API) “glue” The “glue” that holds client/server applications together

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 41 Web-Enabled Databases Web applications requiring databases Web applications requiring databases Customer relationship management (CRM) Customer relationship management (CRM) Business-to-consumer (B2C) Business-to-consumer (B2C) Electronic data interchange (EDI) Electronic data interchange (EDI) Private intranets Private intranets XML-defined Web services XML-defined Web services

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 42 Web-Enabled Databases (cont.) Issues to consider Issues to consider Which technologies to use? Which technologies to use? Security/privacy protection Security/privacy protection Managing huge volumes of data from Internet transactions Managing huge volumes of data from Internet transactions Maintaining data quality Maintaining data quality

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 43 Figure 10-1 Database-enabled intranet/internet environment

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 44 Server-Side Extensions Programs that interact directly with Web servers to handle requests Programs that interact directly with Web servers to handle requests e.g. database-request handling middleware e.g. database-request handling middleware Figure 10-2 Web-to-database middleware

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 45 Figure 10-7 Web services deployment (adapted from Newcomer, 2002)

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 46 Table 1-6 Summary of Database Applications

Chapter 1 © 2009 Pearson Education, Inc. Publishing as Prentice Hall 47 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall