1. Alter – Information Systems 4th ed. © 2002 Prentice Hall 1 Information and Databases

2. Alter – Information Systems 4th ed. © 2002 Prentice Hall 2 Opening Case: eBay A PURE INFORMATION business It creates values purely by processing the information required to conduct online auctions Holds NO inventories Allows both individuals & companies to participate in auctions How auctions operate Powerful (but imperfect) trust mechanisms

3. Alter – Information Systems 4th ed. © 2002 Prentice Hall 3 Basic Ideas for Describing Data

4. Alter – Information Systems 4th ed. © 2002 Prentice Hall 4 Types of Data Predefined data items Text Images Audio Video The only types used by traditional business systems

5. Alter – Information Systems 4th ed. © 2002 Prentice Hall 5 Types of Data in Today’s Information systems Pre-defined Data - numerical or text items whose meaning are specified explicitly. Text - letters, numbers, and other characters where the meaning is not pre-defined. Images - data in the form of pictures Audio - data in the form of sound Video - combination of pictures and sound displayed over time. Future types: taste and smell?

6. Alter – Information Systems 4th ed. © 2002 Prentice Hall 6 Images produced by information systems

7. Alter – Information Systems 4th ed. © 2002 Prentice Hall 7 What Is a Database? A structured collection of ELECTRONICALLY STORED data Controlled & accessed through computers predefined relationshipspredefined types of data items The structure is given by predefined relationships between predefined types of data items May include any of the five types of data

8. Alter – Information Systems 4th ed. © 2002 Prentice Hall 8 Database management system (DBMS) = an integrated set of programs, used to define, update, and control the database

9. Alter – Information Systems 4th ed. © 2002 Prentice Hall 9 Files- Figure 4.2 A set of related records that contain the same fields in the same order and format Key = a fields that uniquely identifies each record

10. Alter – Information Systems 4th ed. © 2002 Prentice Hall 10 Logical vs. Physical Views of the Data People need a model of how the data is stored in the database DATA MODEL = a logical description of the structure of the data Logical view of data = how people think about the data Physical view of the data = how the computer “thinks” about the data

11. Alter – Information Systems 4th ed. © 2002 Prentice Hall 11 Figure 4.3

12. Alter – Information Systems 4th ed. © 2002 Prentice Hall 12 The Process of Accessing Data Push vs. pull Push system Push system = the information is provided to the user automatically Pull system Pull system = the user requests the information each time it is needed Preprogrammedad hoc Preprogrammed vs. ad hoc Push systems are preprogrammed, while pull systems are ad hoc

13. Alter – Information Systems 4th ed. © 2002 Prentice Hall 13 Data Modeling Defining and Organizing the Data

14. Alter – Information Systems 4th ed. © 2002 Prentice Hall 14 Data Modeling: Documenting Information Architecture Information Architecture - a conceptualization of how the information requirements are met by the system. From the user’s viewpoint: What information is in the system? How is the information organized? How can users obtain whatever information they need?

15. Alter – Information Systems 4th ed. © 2002 Prentice Hall 15 Entity Relationship Diagrams What kinds of things does the system collect information about? entities What is the relationship between these entities? Relationship or association among entities What specific information does it collect about each of those things? attributes

16. Alter – Information Systems 4th ed. © 2002 Prentice Hall 16 Entity-relationship diagram for part of a university registration system

17. Alter – Information Systems 4th ed. © 2002 Prentice Hall 17 Types of relationships in entity- relationship

18. Alter – Information Systems 4th ed. © 2002 Prentice Hall 18 Possible Attributes for the Entity Types DEPARTMENT Department identifier College Department head Scheduling coordinator COURSE Course number Department Required of department major (y/n) Course description SECTION Section identification number Semester Year Classroom Start time End time Days of week for class meetings PROFESSOR Employee identification number Name Address Birthdate Office telephone Social Security number STUDENT Student identification number Name Address Birthdate Telephone Gender Ethic group Social Security number OFFICE Office number Building Telephone extension

19. Alter – Information Systems 4th ed. © 2002 Prentice Hall 19 Use of E-R Diagrams E-R Diagrams are actually used for the non-technical purpose of identifying the types of things within the system’s scope and the relationships among these types of things.

20. Alter – Information Systems 4th ed. © 2002 Prentice Hall 20 ERDs help determine what data will be included, and how the database will be structured communication medium Excellent communication medium between users and developers

21. Alter – Information Systems 4th ed. © 2002 Prentice Hall 21 Types of Databases

22. Alter – Information Systems 4th ed. © 2002 Prentice Hall 22 Relational Databases The predominant database technology A set of tables linked through shared key attributes ERDs constitute a good starting point for defining the tables and the keys in a relational database

23. Alter – Information Systems 4th ed. © 2002 Prentice Hall 23 E-R Diagram from a Relational Database – (Figure 4.6 MS-Access)

24. Alter – Information Systems 4th ed. © 2002 Prentice Hall 24 Normalization = a technique for designing a good set of tables Eliminates redundancies and inconsistent dependencies Structured Query Language (SQL) – the standard language for creating and manipulating relational databases

25. Alter – Information Systems 4th ed. © 2002 Prentice Hall 25 Some new Data base Concepts Multi-dimensional databases: most relational database models are optimized to support transaction processing. Business professionals often wish to analyze large amounts of data frequently, e.g. along dimensions of product, time period, and store. There is a significant difference between transaction processing vs. analytical processing. Multi-dimensional databases help support data warehouses which we will discuss further later in the semester.

26. Alter – Information Systems 4th ed. © 2002 Prentice Hall 26 Multidimensional Databases Relational databases are not appropriate when the data in massive databases must be analyzed Multidimensional database – a large database used for data analysis Can be viewed as a single table, where each column represents a different dimension

27. Alter – Information Systems 4th ed. © 2002 Prentice Hall 27 Multi-dimensional Databases Transaction Systems: Insert an order for 300 baseballs Update this passenger’s airline reservation. close-out accounts payable records for this vendor. What is the current checking account balance for this customer? Analytical Support Systems: Did the sales promotion last quarter do better than the same promotion last year? Is the five-day moving average for this security leading or trailing actual prices? Which product line sells best in middle-America and how does this correlate to demographic data.

28. Alter – Information Systems 4th ed. © 2002 Prentice Hall 28 A Multidimensional database

29. Alter – Information Systems 4th ed. © 2002 Prentice Hall 29 Slicing and Dicing

30. Alter – Information Systems 4th ed. © 2002 Prentice Hall 30 Slicing and dicing – analyzing the data in a variety of ways to better understand it, and get answers to business questions

31. Alter – Information Systems 4th ed. © 2002 Prentice Hall 31 Data Warehouses A system designed to support business analysis and management decision making Typically supported by multidimensional databases An alternative to databases used to support business transactions Data mart = a smaller data warehouse used by a business function or department

32. Alter – Information Systems 4th ed. © 2002 Prentice Hall 32 Maintaining a Data warehouse

33. Alter – Information Systems 4th ed. © 2002 Prentice Hall 33 Geographic Information Systems Organizing data so that it can be accessed by pointing at a region on a map. Based on spatial or geographic coordinates. Marketing and planning applications can visualize customers The important distinction between GIS and other types of information systems is not in the database, but in the access method (i.e. through maps).

34. Alter – Information Systems 4th ed. © 2002 Prentice Hall 34 Geographical Information Systems (GISs) Permit the user to access data based on spatial or geographic coordinates Consist of: A database Software that allow data to be used by selecting locations on a map

35. Alter – Information Systems 4th ed. © 2002 Prentice Hall 35 A geographical information system

36. Alter – Information Systems 4th ed. © 2002 Prentice Hall 36 Text & Image Databases TEXT databases = set of electronic documents Individual documents or information within documents can be retrieved Typically use hypertext to link the documents IMAGE databases – store images and their descriptions Increasingly important (online catalogs)

37. Alter – Information Systems 4th ed. © 2002 Prentice Hall 37 Hypermedia Databases and the Web Hypermedia database = a database that uses hypertext links to organize Document Document files Text Images Data Audio Video Executable Executable files

38. Alter – Information Systems 4th ed. © 2002 Prentice Hall 38 The Web Not a hypertext database since its content is not defined and controlled Web page URL Browser HTML XML Applets

39. Alter – Information Systems 4th ed. © 2002 Prentice Hall 39 Retrieving a web page requires passing messages between different computers - Figure 4.13

40. Alter – Information Systems 4th ed. © 2002 Prentice Hall 40 Indexes & search engines Index = a list structure organized to identify and locate documents related to a specific topic Multilayer indexes Search engine = software that identifies Web pages based on user supplied KEYWORDS Query tools for the Web take into account the fact that the Web lacks predefined data definitions

41. Alter – Information Systems 4th ed. © 2002 Prentice Hall 41 Database Management Systems (DBMSs) Control and organize data in the database Facilitate programming based on the data in the database

42. Alter – Information Systems 4th ed. © 2002 Prentice Hall 42 Defining the Database and Access to Data Data definition = identifying and describing all the data elements in the database Also known as a schema Most DBMSs support the definition of subschemas = a “slice” of the database Data definition information is stored in the data dictionary Describes the data metadata

43. Alter – Information Systems 4th ed. © 2002 Prentice Hall 43 Methods for Accessing Data Sequential access Sequential access Records are processed in sequence Useful for many types of scheduled periodic processing Impractical when immediate processing of data is required

44. Alter – Information Systems 4th ed. © 2002 Prentice Hall 44 Figure 4.14 Direct access Direct access – the location of the requested record is calculated May result in collisions

45. Alter – Information Systems 4th ed. © 2002 Prentice Hall 45 Figure 4.15 Indexed access Indexed access Index Index = a table used to locate data Possible to perform both sequential and direct access efficiently indexed sequential access method (ISAM)

46. Alter – Information Systems 4th ed. © 2002 Prentice Hall 46 Processing Transactions Controlling simultaneous access to data Locking – while a transaction uses the data (locks it), all other transactions are prevented from using it

47. Alter – Information Systems 4th ed. © 2002 Prentice Hall 47 Distributed Databases Data is distributed to different locations to match the way many organizations are dispersed Centralized vs. distributed databases – tradeoffs An alternative: database replication – complete or partial copies are stored at remote locations

48. Alter – Information Systems 4th ed. © 2002 Prentice Hall 48 Backup and Recovery Backup = storing additional copies of data Recovery = restoring the database to the state it had prior to a failure Based on the last complete backup + journal of all transactions since the last backup

49. Alter – Information Systems 4th ed. © 2002 Prentice Hall 49 Database Administration Planning for future usage Enforcing database standards Controlling database access Maintaining efficient database operation

50. Alter – Information Systems 4th ed. © 2002 Prentice Hall 50 Some Information Concepts Data Information Knowledge

51. Alter – Information Systems 4th ed. © 2002 Prentice Hall 51 Some Information Concepts Data: Unorganized facts and figures. (raw material) Information: Data that has been processed into a form that is meaningful to the recipient and is of real of perceived value in current or prospective actions or decisions. Information: adds to a representation corrects or confirms previous information has “surprise” value in that it tells us something we did not know, or could not predict. What is a “finished product” to one, may be “raw materials” to someone else.

52. Alter – Information Systems 4th ed. © 2002 Prentice Hall 52 Definitions: Information vs. Knowledge Knowledge: a combination of instincts, ideas, rules, and procedures that guide actions and decisions. Helping to provide the best available knowledge to decision-making is another role of information systems

53. Alter – Information Systems 4th ed. © 2002 Prentice Hall 53 Relationship Between Data, Information, and Knowledge The difference between data and information is easy to remember. It is often cited as the reason why systems that collect large amounts of information fail to meet management’s information needs. There are many methods of converting data into information for decision making. Managers take action based on information about a current situation plus their accumulated knowledge. Actions taken feed the process of accumulating more knowledge (experience). Example: How do medical students become competent physicians?

54. Alter – Information Systems 4th ed. © 2002 Prentice Hall 54 Relationship Between Data, Information, and Knowledge

55. Alter – Information Systems 4th ed. © 2002 Prentice Hall 55 Evaluating Data As a Resource Information quality Information accessibility Information presentation

56. Alter – Information Systems 4th ed. © 2002 Prentice Hall 56 Attributes of Quality Information Timeliness Completeness Conciseness Relevance Accuracy Precision Appropriateness of Form

57. Alter – Information Systems 4th ed. © 2002 Prentice Hall 57 Information Quality Accuracy & precision Accuracy – the extent to which the information represents what it is supposed to represent Precision – the fineness of detail Bias and random error lead to inaccuracy Completeness – the extent to which the available information is appropriate for the task

58. Alter – Information Systems 4th ed. © 2002 Prentice Hall 58 Age & timeliness Age – the amount of time that has passed since the information was produced Timeliness – the extent to which the age of the information is appropriate for the task

59. Alter – Information Systems 4th ed. © 2002 Prentice Hall 59 Source – the person or organization that produced the information Internal or external Formal or informal

60. Alter – Information Systems 4th ed. © 2002 Prentice Hall 60 Special Characteristics of Information Usefulness - depends on combination of quality,accessibility,and presentation. One person’s information may be another person’s noise. Soft data may be as important as hard data. Ownership of information may be hard to maintain. More information is not always better (information overload). Politics can often hide or distort information.

61. Alter – Information Systems 4th ed. © 2002 Prentice Hall 61 Review: Information Needs - Operational vs. Strategic ( See Gorry and Scott-Morton Article ) Time frame - historical vs. predictive for the future Currency - highly current vs. can be quite old Expectation - anticipated vs. surprise Source - largely internal vs. largely external Scope - well-defined, narrow vs. very wide Level of aggregation - detail vs. summary Frequency - real-time vs. periodic Organization - highly structured vs. loosely structured Precision - highly precise vs. not overly precise

62. Alter – Information Systems 4th ed. © 2002 Prentice Hall 62 Question? What special attributes or characteristics of information have affected you as an individual or as part of a group?

63. Alter – Information Systems 4th ed. © 2002 Prentice Hall 63 Information Accessibility Availability – the extent to which the information is available in the information system Admissibility – refers to whether laws, regulations, or culture require or prohibit the use of the information

64. Alter – Information Systems 4th ed. © 2002 Prentice Hall 64 Information Presentation Level of summarization Level of summarization – a comparison between the numbers of individual items on which the data is based and the number of items in the data presented Format Format – the way the information is organized and expressed

65. Alter – Information Systems 4th ed. © 2002 Prentice Hall 65 Information Security ACCESS RESTRICTION – who can access what information under what circumstances ENCRYPTION – converting data into a coded form that unauthorized people cannot decode

66. Alter – Information Systems 4th ed. © 2002 Prentice Hall 66 Determinants of Information Usefulness and Related Roles of Information Systems INFORMATION QUALITY ACCURACY PRECISION COMPLETENESS AGE TIMELINESS SOURCE

67. Alter – Information Systems 4th ed. © 2002 Prentice Hall 67 Determinants of Information Usefulness and Related Roles of Information Systems INFORMATION ACCESSIBILITY AVAILABILITY ADMISSIBILITY INFORMATION PRESENTATION LEVEL OF SUMMARIZATION FORMAT INFORMATION SECURITY ACCESS RESTRICTION ENCRYPTION

68. Alter – Information Systems 4th ed. © 2002 Prentice Hall 68 Models As Components of Information Systems Mental models – the unwritten assumptions and beliefs used by people when thinking about a topic Often inconsistent Mathematical models – a formal representation of the relationships between variables Compensate for the human inability to think of too many details at the same time

69. Alter – Information Systems 4th ed. © 2002 Prentice Hall 69 What-if questions Explore the effect of alternative assumptions about the key variables in a mathematical model Virtual reality – a simulation of reality that permits the participant to interact with the simulated environment

70. Alter – Information Systems 4th ed. © 2002 Prentice Hall 70 Do managers expect the truth?