1. To navigate the slide presentation, use the navigation bar on the left OR use your right and left arrow keys. Move your mouse over the key terms throughout the presentation to see a definition. Click to view reference figures. For further exploration, links to selected web sites are included. Click under this banner throughout the presentation. Chapter 8 Home Page – Welcome!

2. 2 Chapter Objectives  Explain data design concepts and data structures  Describe file processing systems  Explain database systems and define the components of a database management system (DBMS)  Describe Web-based data design

3. 3 Chapter Objectives  Explain data design terminology, including entities, fields, common fields, records, files, tables, and key fields  Describe data relationships, draw an entity- relationship diagram, define cardinality and use cardinality notation  Explain the concept of normalization  Explain the importance of codes and describe various coding schemes

4. 4 Chapter Objectives  Describe relational and object-oriented database models  Explain data warehousing and data mining  Differentiate between logical and physical storage and records  Explain data control measures

5. 5 Introduction  You will develop a physical plan for data organization, storage, and retrieval  Begins with a review of data design concepts and terminology, then discusses file-based systems and database systems, including Web- based databases  Concludes with a discussion of data storage and access, including strategic tools such as data warehousing and data mining, physical design issues, logical and physical records, data storage formats, and data controls

6. 6 Data Design Concepts  Before constructing an information system, a systems analyst must understand basic design concepts, including data structures and the characteristics of file processing and database systems, including Web-based database design

7. 7 Data Design Concepts  Data Structures Data Structures – A file or table contains data about people, places or events that interact with the systemfiletable – File-oriented system File-oriented system – File processing File processing – Database system Database system Figure 8-2 Figure 8-3

8. 8 Data Design Concepts  Overview of File Processing – Companies mainly use file processing to handle large volumes of structured data on a regular basis – Although much less common today, file processing can be more efficient and cost- effective in certain situations Figure 8-4

9. 9 Data Design Concepts  Overview of File Processing – Potential problems Data redundancy Data integrity Rigid data structure

10. 10 Data Design Concepts  Overview of File Processing – Various types of files Master file Table file Transaction file Work file Security file History file

11. 11 Data Design Concepts  The Evolution from File Systems to Database Systems – A properly design database system offers a solution to the problems of file processing – Provides an overall framework that avoids data redundancy and supports a real-time, dynamic environment Figure 8-5

12. 12 Data Design Concepts  The Evolution from File Systems to Database Systems – A database management system (DBMS) is a collection of tools, features, and interfaces that enables users to add, update, manage, access, and analyze the contents of a databasedatabase management system (DBMS) – The main advantage of a DBMS is that it offers timely, interactive, and flexible data access

13. 13 Data Design Concepts The Evolution from File Systems to Database Systems Advantages Scalability Better support for client/server systemsclient/server Economy of scale Flexible data sharing Enterprise-wide application – database administrator (DBA)database administrator (DBA) Stronger standards

14. 14 Data Design Concepts  The Evolution from File Systems to Database Systems – Advantages Controlled redundancy Better security Increased programmer productivity Data independence

15. 15 Data Design Concepts  Database Tradeoffs – Because DBMSs are powerful, they require more expensive hardware, software, and data networks capable of supporting a multi-user environment – More complex than a file processing system – Procedures for security, backup, and recovery are more complicated and critical

16. 16 DBMS Components  A DBMS provides an interface between a database and users who need to access the data  In addition to interfaces for users, database administrators, and related systems, a DBMS also has a data manipulation language, a schema and subschemas, and a physical data repository Figure 8-6

17. 17 DBMS Components  Interfaces for Users, Database Administrators, and Related Systems – Users Query language Query by example (QBE) SQL (structured query language) – Database Administrators A DBA is responsible for DBMS management and support Figure 8-7

18. 18 DBMS Components  Interfaces for Users, Database Administrators, and Related Systems – Related information systems A DBMS can support several related information systems that provide input to, and require specific data from, the DBMS

19. 19 DBMS Components  Data Manipulation Language – A data manipulation language (DML) controls database operations, including storing, retrieving, updating, and deleting datadata manipulation language (DML)

20. 20 DBMS Components  Schema – The complete definition of a database, including descriptions of all fields, tables, and relationships, is called a schemaschema – You also can define one or more subschemassubschemas

21. 21 DBMS Components  Physical Data Repository – The data dictionary is transformed into a physical data repository, which also contains the schema and subschemas – The physical repository might be centralized, or distributed at several locations – ODBC – open database connectivity ODBC – JDBC – Java database connectivity JDBC

22. 22 Web-Based Database Design  The following sections discuss the characteristics of Web-based design, Internet terminology, connecting a database to the Web, and data security on the Web

23. 23 Web-Based Database Design  Characteristics of Web-Based Design – In a Web-based design, the Internet serves as the front end, or interface for the database management system. Internet technology provides enormous power and flexibility – Web-based systems are popular because they offer ease of access, cost-effectiveness, and worldwide connectivity Figure 8-8

24. 24 Web-Based Database Design  Internet Terminology – Web browser Web browser – Web page Web page – HTML (Hypertext Markup Language) HTML (Hypertext Markup Language) – Tags Tags – Web server Web server – Web site Web site For more information about HTML, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the HTML link.

25. 25 Web-Based Database Design  Internet Terminology – Intranet Intranet – Extranet Extranet – Protocols Protocols – Web-centric Web-centric – Clients Clients – Servers Servers

26. 26 Web-Based Database Design  Connecting a Database to the Web – Database must be connected to the Internet or intranet Middleware Adobe ColdFusion Figure 8-9 Figure 8-10

27. 27 Web-Based Database Design  Data Security – Web-based data must be totally secure, yet easily accessible to authorized users – To achieve this goal, well-designed systems provide security at three levels: the database itself, the Web server, and the telecommunication links that connect the components of the system

28. 28 Data Design Terminology  Definitions – Entity Entity – Table or file – Field Field Attribute Common field – Record Record Tuple Figure 8-11

29. 29 Data Design Terminology  Key Fields Key Fields – Primary key Primary key Combination key Composite key Concatenated key Multi-valued key Figure 8-12

30. 30 Data Design Terminology  Key Fields – Candidate key Candidate key Nonkey field – Foreign key Foreign key – Secondary key Secondary key

31. 31 Data Design Terminology  Referential Integrity Referential Integrity – Validity checks can help avoid data input errors – In a relational database, referential integrity means that a foreign key value cannot be entered in one table unless it matches an existing primary key in another table – Orphan Orphan Figure 8-13 For more information about Referential Integrity, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Referential Integrity link.

32. 32 Entity-Relationship Diagrams  An entity is a person, place, thing, or event for which data is collected and maintained  Entity-relationship diagram (ERD) Entity-relationship diagram (ERD)  An ERD provides an overall view of the system, and a blueprint for creating the physical data structures For more information about Entity-Relationship Diagrams, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Entity-Relationship Diagrams link.

33. 33 Entity-Relationship Diagrams  Drawing an ERD – The first step is to list the entities that you identified during the fact-finding process and to consider the nature of the relationships that link them – A popular method is to represent entities as rectangles and relationships as diamond shapes Figure 8-14

34. 34 Entity-Relationship Diagrams  Types of Relationships – Three types of relationships can exist between entities – One-to-one relationship (1:1) One-to-one relationship 1:1 – One-to-many relationship (1:M) One-to-many relationship 1:M – Many-to-many relationship (M:N) Many-to-many relationship M:N Associative entity Figure 8-15 Figure 8-16 Figure 8-17 Figure 8-18

35. 35 Entity-Relationship Diagrams  Cardinality Cardinality Cardinality notation Crow’s foot notation Unified Modeling Language (UML) Figure 8-19 Figure 8-20 Figure 8-21 For more information about Cardinality, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Cardinality link.

36. 36 Normalization  Normalization Normalization  Table design Table design  Involves four stages: unnormalized design, first normal form, second normal form, and third normal form  Most business-related databases must be designed in third normal form For more information about Normalization, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Normalization link.

37. 37 Normalization  Standard Notation Format – Designing tables is easier if you use a standard notation format to show a table’s structure, fields, and primary keystandard notation format Example: NAME (FIELD 1, FIELD 2, FIELD 3)

38. 38 Normalization  Repeating Groups and Unnormalized Design – Repeating group Repeating group Often occur in manual documents prepared by users – Unnormalized Unnormalized Figure 8-22

39. 39 Normalization  First Normal Form – A table is in first normal form (1NF) if it does not contain a repeating groupfirst normal form (1NF) – To convert, you must expand the table’s primary key to include the primary key of the repeating group Figure 8-23

40. 40 Normalization  Second Normal Form – To understand second normal form (2NF), you must understand the concept of functional dependencesecond normal form (2NF) – Field X is functionally dependent on field Y if the value of field X depends on the value of field Yfunctionally dependent

41. 41 Normalization  Second Normal Form – A standard process exists for converting a table from 1NF to 2NF 1.First, create and name a separate table for each field in the existing primary key 2.Next, create a new table for each possible combination of the original primary key fields 3.Finally, study the three tables and place each field with its appropriate primary key Figure 8-24

42. 42 Normalization  Second Normal Form – Four kinds of problems are found with 1NF description that do not exist with 2NF Consider the work necessary to change a particular product’s design 1NF tables can contain inconsistent data Adding a new product is a problem Deleting a product is a problem

43. 43 Normalization  Third Normal Form – 3NF design avoids redundancy and data integrity problems that still can exist in 2NF designs – A table design is in third normal form (3NF) if it is in 2NF and if no nonkey field is dependent on another nonkey fieldthird normal form (3NF) Figure 8-25

44. 44 Normalization  Third Normal Form – To convert the table to 3NF, you must remove all fields from the 2NF table that depend on another nonkey field and place them in a new table that uses the nonkey field as a primary key Figure 8-26

45. 45 Normalization  A Normalization Example – To show the normalization process, consider the familiar situation in Figure 8-27 which might depict several entities in a school advising system: ADVISOR, COURSE, and STUDENT Figure 8-27 Figure 8-28 Figure 8-30 Figure 8-31 Figure 8-29 Figure 8-32 Figure 8-33

46. 46 Using Codes During System Design  Overview of CodesCodes – Because codes often are used to represent data, you encounter them constantly in your everyday life – They save storage space and costs, reduce transmission time, and decrease data entry time – Can reduce data input errors Figure 8-34

47. 47 Using Codes During System Design  Types of Codes 1.Sequence codesSequence codes 2.Block sequence codesBlock sequence codes 3.Alphabetic codesAlphabetic codes a.Category codesCategory codes b.Abbreviation codes – mnemonic codesAbbreviation codesmnemonic codes Figure 8-35

48. 48 Using Codes During System Design  Types of codes 4.Significant digit codesSignificant digit codes 5.Derivation codesDerivation codes 6.Cipher codesCipher codes 7.Action codesAction codes Figure 8-36 Figure 8-37

49. 49 Using Codes During System Design  Developing a Code 1.Keep codes concise 2.Allow for expansion 3.Keep codes stable 4.Make codes unique 5.Use sortable codes

50. 50 Using Codes During System Design  Developing a Code 6.Avoid confusing codes 7.Make codes meaningful 8.Use a code for a single purpose 9.Keep codes consistent

51. 51 Steps in Database Design 1.Create the initial ERD 2.Assign all data elements to entities 3.Create 3NF designs for all tables 4.Verify all data dictionary entries – After creating your final ERD and normalized table designs, you can transform them into a database Figure 8-38 Figure 8-39 Figure 8-40

52. 52 Database Models  Relational Databases – The relational model was introduced during the 1970s and became popular because it was flexible and powerfulrelational model – Because all the tables are linked, a user can request data that meets specific conditions – New entities and attributes can be added at any time without restructuring the entire database Figure 8-41 Figure 8-42

53. 53 Database Models  Object-Oriented Databases – Many systems developers are using object- oriented database (OODB) design as a natural extension of the object-oriented analysis processobject- oriented database (OODB) Object Database Management Group (ODMG) Each object has a unique object identifierobject identifier Figure 8-43 Figure 8-44

54. 54 Data Storage and Access  Data storage and access involve strategic business tools  Strategic tools for data storage and access – Data warehouse – dimensions Data warehousedimensions – Data mart Data mart Figure 8-45 For more information about Data Warehousing, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Data Warehousing link. Figure 8-46

55. 55 Data Storage and Access  Strategic tools for data storage and access – Data Mining Data Mining Increase average pages viewed per session. Increase number of referred customers Reduce clicks to closeclicks to close Increase checkouts per visit Increase average profit per checkout Clickstream storage – market basket analysisClickstream storagemarket basket analysis For more information about Data Mining, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Data Mining link. Figure 8-47

56. 56 Data Storage and Access  Logical and Physical Storage – Logical storage Logical storage Characters Date element or data itemDate elementdata item Logical record – Physical storage Physical storage Physical record or blockPhysical recordblock Buffer Blocking factor

57. 57 Data Storage and Access  Data Storage Formats – Binary digits Binary digits – Bit Bit – Byte Byte – EBCDIC and ASCII EBCDICASCII – Unicode - internationalize Unicodeinternationalize Figure 8-48

58. 58 Data Storage and Access  Data Storage Formats – Binary Binary storage format Integer format Long integer format Other binary formats exist for efficient storage of exceedingly long numbers

59. 59 Data Storage and Access  Selecting a Data Storage Format – In many cases, a user can select a specific data storage format – For example, when using Microsoft Office, you can store documents, spreadsheets, and databases in Unicode-compatible form by using the font called Arial Unicode MS – Best answer is it depends on the situation

60. 60 Data Storage and Access  Date Fields – Most date formats now are based on the model established by the International Organization for Standardization (ISO)International Organization for Standardization (ISO) – Can be sorted easily and used in comparisons – Absolute date Absolute date – Best method depends on how the specific date will be printed, displayed or used in a calculation Figure 8-49

61. 61 Data Control  File and database control must include all measures necessary to ensure that data storage is correct, complete, and secure  A well-designed DBMS must provide built-in control and security features, including subschemas, passwords, encryption, audit trail files, and backup and recovery procedures to maintain data Figure 8-50 For more information about Data Control, visit scsite.com/sad7e/more, scsite.com/sad7e/more locate Chapter 8 and then the Data Control link.

62. 62 Data Control  User ID User ID  Password Password  Permissions Permissions  Encryption Encryption

63. 63 Data Control  Backup Backup  Recovery procedures Recovery procedures  Audit log files Audit log files  Audit fields Audit fields

64. 64 Chapter Summary  Files and tables contain data about people, places, things, or events that affect the information system  DBMS designs are more powerful and flexible than traditional file-oriented systems

65. 65 Chapter Summary  Data design tasks include creating an initial ERD; assigning data elements to an entity; normalizing all table designs; and completing the data dictionary entries for files, records, and data elements  A code is a set of letters or numbers used to represent data in a system  The most common database models are relational and object-oriented

66. 66 Chapter Summary  Logical storage is information seen through a user’s eyes, regardless of how or where that information actually is organized or stored  Physical storage is hardware-related and involves reading and writing blocks of binary data to physical media  File and database control measures include limiting access to the data, data encryption, backup/recovery procedures, audit-trail files, and internal audit fields

67. 67 Test Yourself 1.List 2 database management system (DBMS) components.

68. 68 Test Yourself 1.List 2 database management system (DBMS) components. 1.Interfaces 2.Data manipulation language 3.Schema 4.Physical data repository

69. 69 Test Yourself 2.True/False: Some amount of data duplication is permissible in file oriented systems, but is avoided in database systems.

70. 70 Test Yourself 2.True/False: Some amount of data duplication is permissible in file oriented systems, but is avoided in database systems. True

71. 71 Test Yourself 3.Match the terms on the left with the correct definitions on the right. 1. Primary key 2. Secondary key 3. Foreign key 4. Candidate key a.A non-unique field or combination of fields that can be used to access records. b.a field or combination of fields that uniquely and minimally identifies a particular entity. c.Any field that could serve as a primary key is called this term. d.A field in one table that must match a primary key value in another table to establish a relationship.

72. 72 Test Yourself 3.Match the terms on the left with the correct definitions on the right. 1. Primary key 2. Secondary key 3. Foreign key 4. Candidate key a.A non-unique field or combination of fields that can be used to access records. b.a field or combination of fields that uniquely and minimally identifies a particular entity. c.Any field that could serve as a primary key is called this term. d.A field in one table that must match a primary key value in another table to establish a relationship.

73. 73 Test Yourself 4.Describe the relationship by filling in the diamond and labeling the cardinality (i.e. 1:1, 1:M, M:N) StudentBook TV Station Social Security Number Movies Person

74. 74 Test Yourself 4.Describe the relationship by filling in the diamond and labeling the cardinality (i.e. 1:1, 1:M, M:N) StudentBook TV Station Social Security Number Movies Person Owns Assigned to Shows 1 M N 1 1 M

75. 75 Test Yourself 5.True/False: Cardinality is a graphical model of the information system that depicts the relationships among system entities.

76. 76 Test Yourself 5.True/False: Cardinality is a graphical model of the information system that depicts the relationships among system entities. False

77. 77 Test Yourself 6.Briefly explain the following normalization rules: First Normal Form (1NF) Second Normal Form (2NF) Third Normal Form (3NF)

78. 78 Test Yourself 6.Briefly explain the following normalization rules: First Normal Form (1NF) - Record is 1NF if there are no repeating groups Second Normal Form (2NF) - To be in 2NF, a record must be in 1NF, and all nonkey fields are functionally dependent on the entire primary key Third Normal Form (3NF) - In 3NF, all nonkey fields are functionally dependent on the primary key, the entire key, and nothing but the key

79. 79 Test Yourself 7.The relationship between an ORDER DATE and an ORDER #, illustrates the concept of _______ _________.

80. 80 Test Yourself 7.The relationship between an ORDER DATE and an ORDER #, illustrates the concept of functional dependence.

81. 81 Test Yourself 8.List the 4 steps of database design that are followed after normalizing record designs or tables.

82. 82 Test Yourself 8.List the 4 steps of database design that are followed after normalizing record designs or tables. 1. Create the initial ERD 2.Assign all data elements to entities 3.Create 3NF designs for all records, taking care to identify all primary, secondary, and foreign keys 4.Verify all data dictionary entries

83. 83 Test Yourself 9.A logical record/physical record is the smallest unit of data that is accessed by the operating system.

84. 84 Test Yourself 9.A physical record is the smallest unit of data that is accessed by the operating system.

85. 85 Test Yourself 10. True/False: Date formats now are based on the model established by the International Organization for Standardization.

86. 86 Test Yourself 10. True/False: Date formats now are based on the model established by the International Organization for Standardization. True.

87. Systems Analysis & Design 7 th Edition End Chapter 8