Chapter 3: Data Modeling Introduction An Overview of Databases Steps in Developing a Database Using Resources, Events and Agents Model Normalization Chapter 3-1 Introduction Uses of a modern AIS  Systematically  Provide  Easy record data convenient and useful formats access to information Chapter 3-2 What is a Database? Collection of organized data Used by many different computer applications Manipulated by database management systems (DBMS) Chapter 3-3 Significance of a Database Critical information Volume Distribution Privacy Irreplaceable data Need for accuracy Internet uses Chapter 3-4 Storing Data in Databases Data must be stored and organized systematically Three important concepts: Data hierarchy  Record structures  Database keys  Chapter 3-5 Data Hierarchy Data organization in ascending order: Data field Record File Database Chapter 3-6 Record Structures Data fields in each record of a database table Structure is usually fixed Example Chapter 3-7 Database Keys Primary Key Unique to each record Foreign Keys Enable referencing of one or more records Matches primary key of related table Chapter 3-8 Records Combined Into Report Chapter 3-9 Additional Database Issues Administration  Database Administrator Documentation  Includes a variety of descriptions  Structures, Contents, Security Features  Data Dictionary  Metadata Chapter 3-10 Study Break #3 - Answer In the REA model, the “A” stands for: A Agents B Additions C Accounts D Associations Chapter 3-32 Study Break #4 Which of these is not a cardinality between two database entities? A One-to-one B None-to-none C One-to-many D Many-to-many Chapter 3-33 Study Break #4 - Answer Which of these is not a cardinality between two database entities? A One-to-one B None-to-none C One-to-many D Many-to-many Chapter 3-34 Normalization Normalization    Methodology ensuring attributes are stored in most appropriate tables Design promotes accuracy Avoids redundancy of data storage Levels    First normal form Second normal form Third normal form Chapter 3-35 Unnormalized Data Chapter 3-36 First Normal Form In First Normal Form (1 NF) when:  All data fields are singular  Each attribute has one value Problems  Data redundancy  Insertion anomaly  Deletion anomaly Chapter 3-37 First Normal Form Example Chapter 3-38 Second Normal Form In Second Normal Form (2 NF) when:  It is in NF  All data items depend on primary record key Benefits  More efficient design  Eliminates data redundancy Chapter 3-39 Second Normal Form Example Chapter 3-40 Third Normal Form In Third Normal Form (3 NF) when:  It is in NF  Does not contain transitive dependencies  Data field A does not determine data field B Ultimate Goal  Create database in NF Chapter 3-41 Third Normal Form Example Chapter 3-42 Study Break #5 A database is in third normal form (3NF) if it is second normal form and: A All the data attributes in a record are well defined B All the data attributes in a record depend on the record key C The data contain to transitive dependencies D The data can be stored in two or more separate tables Chapter 3-43 Study Break #5 - Answer A database is in third normal form (3NF) if it is second normal form and: A All the data attributes in a record are well defined B All the data attributes in a record depend on the record key C The data contain to transitive dependencies D The data can be stored in two or more separate tables Chapter 3-44 Copyright Copyright 2012 John Wiley & Sons, Inc All rights reserved Reproduction or translation of this work beyond that permitted in Section 117 of the 1976 United States Copyright Act without the express written permission of the copyright owner is unlawful Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc The purchaser may make backup copies for his/her own use only and not for distribution or resale The Publisher assumes no responsibility for errors, omissions, or damages, caused by the use of these programs or from the use of the information contained herein Chapter 3-45 Chapter Chapter 3-46 ... convenient and useful formats access to information Chapter 3-2 What is a Database? Collection of organized data Used by many different computer applications Manipulated by database management systems. .. Database Tables Chapter 3-20 Identify Events and Entities Types of Events  Business  Economic Types of Database Entities  Entities  Agents  Resources Chapter 3-21 Entity Examples Chapter 3-22... Relationship Tables Chapter 3-29 Schematic of Database Tables Chapter 3-30 Study Break #3 In the REA model, the “A” stands for: A Agents B Additions C Accounts D Associations Chapter 3-31