1. Chapter 4-1

2. Chapter 4-2 Chapter 4: Data Modeling Introduction An Overview of Databases Steps in Creating a Database Using REA Creating Database Tables and Records

3. Chapter 4-3 Introduction Uses of a modern AIS  Systematically record data  Provide convenient and useful formats  Easy access to information

4. Chapter 4-4 What is a Database? Collection of related data Stored in computerized, linked files Manipulated by database management systems (DBMS)

5. Chapter 4-5 Importance of a Database? Valuable information Volume Complexity Privacy Irreplaceable data Need for accuracy Internet uses

6. Chapter 4-6 Data must be stored and organized efficiently Three important concepts:  Data hierarchy  Record structures  Record keys Storing Data in Databases

7. Chapter 4-7 Data Hierarchy Data organization in ascending order:  Bit (binary digit)  Byte (eight bits)  Data field  Record  File  Database

8. Chapter 4-8 Record Structures Data fields in each record Structure is usually fixed Example

9. Chapter 4-9 Record Keys Primary Record Key  Unique to each record Secondary Record Key  Non-unique identifiers  Used for searching files Foreign Keys

10. Chapter 4-10 Records Combined Into Report

11. Chapter 4-11 Additional Database Concerns Administration  Database Administrator Documentation  Includes a variety of descriptions  Structures, Contents, Security Features  Data Dictionary  Metadata

12. Chapter 4-12 Data Dictionary Example

13. Chapter 4-13 Additional Database Concerns Data Integrity  Data Integrity controls  Designed by database developers Processing Accuracy and Completeness  Transaction controls  Ensures transaction processing

14. Chapter 4-14 Additional Database Concerns Concurrency  Concurrency controls  Prevent multi-user access at same time Backup and Security  Ability to recreate data  Prevent unauthorized access  View controls

15. Chapter 4-15 Which of these is not part of the “data hierarchy” (within the context of databases)? A.Record B.Bit C.Character D.Data type Study Break #1

16. Chapter 4-16 Which of these is not part of the “data hierarchy” (within the context of databases)? A.Record B.Bit C.Character D.Data type Study Break #1 - Answer

17. Chapter 4-17 Within the context of databases, the term “concurrency” refers to the possibility that: A.A customer of one store might also be a customer of another store B.Two database users might want to access the same record at the same time C.A credit entry for a customer requires a debit entry for a matching account D.None of these Study Break #2

18. Chapter 4-18 Within the context of databases, the term “concurrency” refers to the possibility that: A.A customer of one store might also be a customer of another store B.Two database users might want to access the same record at the same time C.A credit entry for a customer requires a debit entry for a matching account D.None of these Study Break #2 - Answer

19. Chapter 4-19 REA Model Resources  Organization’s assets Events  Activities associated with a business processes Agents  People associated with business activities

20. Chapter 4-20 Identify Business and Economic Events Identify Entities Identify Relationships Among Entities Steps in Creating Databases with REA

21. Chapter 4-21 Create Entity-Relationship Diagrams Identify Attributes Entities Create Database Tables and Records to Validate the Database Steps in Creating Databases with REA

22. Chapter 4-22 Types of Events  Business  Economic Types of Database Entities  Events  Agents  Resources Identify Events and Entities

23. Chapter 4-23 Entity Examples

24. Chapter 4-24 Identify Relationships Among Entities Types of Relationships  Direct relationship  Indirect relationship Cardinalities  Nature of relationships among entities

25. Chapter 4-25 Cardinality Relationships Notations  One-to-one (1,1)  One-to-many (1,N)  None-to-one (0,1)  None-to-many (0,N)  Many-to-many (N,N) Purpose  Occurrence of one entity  Associated with occurrence of one event of another entity

26. Chapter 4-26 Purpose  Diagram entities  Relationships among entities Structure  Diamond symbols for relationships  Notations (1, 0, or N) for cardinalities Entity-Relationship Diagram

27. Chapter 4-27 E-R Diagram Symbols

28. Chapter 4-28 E-R Diagram With Cardinalities

29. Chapter 4-29 Organizing Database Records Database Structure  Method used to organize records  Develop efficient structure  Access data quickly and easily Three Types of Structures  Hierarchical  Network  Relational

30. Chapter 4-30 Hierarchical Structures Tree Structures  Successive levels of data  Inverted tree-like pattern Record Types  Parent records  Child records  Sibling records

31. Chapter 4-31 Network Structures Can link related records Capture many-to-many relationships Accomplished using pointer fields

32. Chapter 4-32 Relational Structures Provide greater flexibility Define relationships at different times  As database is created  At later points when relationships are identified

33. Chapter 4-33 Relational Structures

34. Chapter 4-34 Schematic of Database Tables

35. Chapter 4-35 In the REA model, the “A” stands for: A.Agents B.Additions C.Accounts D.Associations Study Break #3

36. Chapter 4-36 In the REA model, the “A” stands for: A.Agents B.Additions C.Accounts D.Associations Study Break #3 - Answer

37. Chapter 4-37 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 Study Break #4

38. Chapter 4-38 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 Study Break #4 - Answer

39. Chapter 4-39 A parent-child relationship between two records is characteristic of: A.Pyramid databases B.Network databases C.Hierarchical databases D.Family databases Study Break #5

40. Chapter 4-40 A parent-child relationship between two records is characteristic of: A.Pyramid databases B.Network databases C.Hierarchical databases D.Family databases Study Break #5 - Answer

41. Chapter 4-41 Creating Database Tables and Records An Introduction to Microsoft Access Creating Database Tables Creating Records Creating Database Relationships Guidelines for Creating Database Tables and Records

42. Chapter 4-42 Introduction to Microsoft Access A popular relational database Used by many businesses and individuals Used for small database applications

43. Chapter 4-43 Microsoft Access – Opening Screen

44. Chapter 4-44 Microsoft Access – Getting Started

45. Chapter 4-45 Creating Database Tables – Defining Record Format Field Name  Names assigned to the data fields Data Type  Specified for each data field Description  Optional field  Defines record structures

46. Chapter 4-46 Creating Database Tables – Opening Screen

47. Chapter 4-47 Creating Database Tables – Record Format

48. Chapter 4-48 Creating Records Utilize datasheet view to input data

49. Chapter 4-49 Creating Database Relationships Purpose  link tables together  enable users to create multi-table reports Steps in Creating Database Relationships  Launch the relationships window  Select tables  Link the tables

50. Chapter 4-50 Creating Database Relationships – Linking Tables

51. Chapter 4-51 Creating Database Relationships – Multi-Table Relationships

52. Chapter 4-52 Guidelines for Creating Database Tables and Records Design first  Create tables and records last Name tables systematically  Use conventional tbl prefixes Use mnemonic names for data fields Assign correct data types to data fields

53. Chapter 4-53 Guidelines for Creating Database Tables and Records Data fields that link tables must be the same data type Limit the size of text data fields to reasonable lengths Use input masks

54. Chapter 4-54 Copyright Copyright 2010 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.

55. Chapter 4-55 Chapter 4