1. © 2005 by Prentice Hall 1 Chapter 1: The Database Environment Modern Database Management 7 th Edition Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden

2. Chapter 1 © 2005 by Prentice Hall 2 Objectives Definition of terms Definition of terms Explain growth and importance of databases Explain growth and importance of databases Name limitations of conventional file processing Name limitations of conventional file processing Identify categories of databases Identify categories of databases Explain advantages of databases Explain advantages of databases Identify costs and risks of databases Identify costs and risks of databases List components of database environment List components of database environment Describe evolution of database systems Describe evolution of database systems

3. Chapter 1 © 2005 by Prentice Hall 3 Definitions Database: organized collection of logically related data Database: organized collection of logically related data Data: stored representations of meaningful objects and events that have meaning and Data: stored representations of meaningful objects and events that have meaning and importance in the user’s environment. importance in the user’s environment. Structured: numbers, text, dates Structured: numbers, text, dates (are stored in tabular form, in tables, relations, (are stored in tabular form, in tables, relations, arrays, spreadsheets, etc.) arrays, spreadsheets, etc.) Unstructured (multimedia): images, video, documents Unstructured (multimedia): images, video, documents

4. Chapter 1 © 2005 by Prentice Hall 4 Information Information: data processed to increase knowledge in the person using the data Information: data processed to increase knowledge in the person using the data For example, consider the following list of facts: For example, consider the following list of facts: Baker, Kenneth D. 324917628 Baker, Kenneth D. 324917628 Doyle, Joan E. 476193248 Doyle, Joan E. 476193248 Finkle, Clive R. 548429344 Finkle, Clive R. 548429344 Lewis, John C. 551742186 Lewis, John C. 551742186 These facts satisfy our definition of data, but they are useless in their present form These facts satisfy our definition of data, but they are useless in their present form

5. Chapter 1 © 2005 by Prentice Hall 5 Convert data into information by adding a few Additional data items and providing some structure Figure 1-1a Data in Context Context helps users understand data, useful information to some user, such as the course instructor

6. Chapter 1 © 2005 by Prentice Hall 6 Graphical displays turn data into useful information that managers can use for decision making and interpretation

7. Chapter 1 © 2005 by Prentice Hall 7 Metadata In practice, databases today may contain In practice, databases today may contain either data or information (or both) either data or information (or both) Metadata: data that describes the properties or characteristics of end user data, and the context of that data Metadata: data that describes the properties or characteristics of end user data, and the context of that data Enable database designers and users to Enable database designers and users to understand what data exist, what the data understand what data exist, what the data mean, and what the fine distinctions are mean, and what the fine distinctions are between seemingly similar data items between seemingly similar data items

8. Chapter 1 © 2005 by Prentice Hall 8 Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and data context

9. Chapter 1 © 2005 by Prentice Hall 9 Database Management Systems A software system that is used to create, A software system that is used to create, maintain, and provide controlled access to maintain, and provide controlled access to user database user database A DBMS also provides facilities for controlling data access, enforcing data integrity, managing concurrency control, and restoring a database A DBMS also provides facilities for controlling data access, enforcing data integrity, managing concurrency control, and restoring a database

10. Chapter 1 © 2005 by Prentice Hall 10 Traditional File Processing Systems You should have at least some familiarity with file processing systems for the following reasons: You should have at least some familiarity with file processing systems for the following reasons: File processing systems are still widely used today, especially for backing up db systems File processing systems are still widely used today, especially for backing up db systems Understanding the problems and limitations inherent in file processing systems can help us avoid these same problems when designing database systems Understanding the problems and limitations inherent in file processing systems can help us avoid these same problems when designing database systems

11. Chapter 1 © 2005 by Prentice Hall 11 Pine Valley Furniture Company (PVFC) PVFC manufactures high-quality, all-wood furniture and distributes it to retail stores nationwide. Among the firm’s several product lines are computer desks and entertainment centers. Customers submit orders to PVFC by any of several means: telephone, mail, fax, or electronic forms via the internet. The company employs a total of about 100 persons at the present time and is experiencing rapid growth PVFC manufactures high-quality, all-wood furniture and distributes it to retail stores nationwide. Among the firm’s several product lines are computer desks and entertainment centers. Customers submit orders to PVFC by any of several means: telephone, mail, fax, or electronic forms via the internet. The company employs a total of about 100 persons at the present time and is experiencing rapid growth

12. Chapter 1 © 2005 by Prentice Hall 12 Pine Valley Furniture Company (PVFC) Early computer applications at PVFC (during the 1980) used the traditional file processing approach. This approach to information systems design focused on the data processing needs of individual departments rather than on evaluating the overall information needs of the organization Early computer applications at PVFC (during the 1980) used the traditional file processing approach. This approach to information systems design focused on the data processing needs of individual departments rather than on evaluating the overall information needs of the organization Each application program or system that was developed was designed to meet the needs of the particular requesting department or user group. Thus, no overall map, plan, or model guided application growth Each application program or system that was developed was designed to meet the needs of the particular requesting department or user group. Thus, no overall map, plan, or model guided application growth

13. Chapter 1 © 2005 by Prentice Hall 13 Figure 1-2 Three file processing systems at Pine Valley Furniture (old file processing systems ) Duplicate Data

14. Chapter 1 © 2005 by Prentice Hall 14 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 (File descriptions are stored within each application program that accesses a given file) (File descriptions are stored within each application program that accesses a given file) Duplication of Data Duplication of Data Different systems/programs have separate copies of the same data (Because applications are often developed independently) Different systems/programs have separate copies of the same data (Because applications are often developed independently) Limited Data Sharing Limited Data Sharing No centralized control of data (each application has its own private files) No centralized control of data (each application has its own private files)

15. Chapter 1 © 2005 by Prentice Hall 15 Disadvantages of File Processing Lengthy Development Times Lengthy Development Times Programmers must design their own file formats (each new application requires that the developer essentially start from scratch by designing new file formats and descriptions and then writing the file access logic for each new program Programmers must design their own file formats (each new application requires that the developer essentially start from scratch by designing new file formats and descriptions and then writing the file access logic for each new program Excessive Program Maintenance Excessive Program Maintenance The preceding factors all combine to create a heavy program maintenance load The preceding factors all combine to create a heavy program maintenance load 80% of of information systems budget 80% of of information systems budget

16. Chapter 1 © 2005 by Prentice Hall 16 Problems with Data Dependency Each application programmer must maintain its own data Each application programmer must maintain its 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

17. Chapter 1 © 2005 by Prentice Hall 17 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: When data changes in one file, could cause inconsistencies When data changes in one file, could cause inconsistencies Compromises data integrity Compromises data integrity

18. Chapter 1 © 2005 by Prentice Hall 18 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)

19. Chapter 1 © 2005 by Prentice Hall 19 Database approach at PVFC DBMS manages data resources like an operating system manages hardware resources

20. Chapter 1 © 2005 by Prentice Hall 20 Elements of the Database Approach Enterprise Data Model Enterprise Data Model Graphical model showing high-level entities for the organization and relationships among those entities (entity is an object or concept that is important to the business) Graphical model showing high-level entities for the organization and relationships among those entities (entity is an object or concept that is important to the business) 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, and client-server Networks and telecommunications, distributed databases, and client-server 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

21. Chapter 1 © 2005 by Prentice Hall 21 Database approach at PVFC PVFC’s first step in converting to a database approach was to develop a list of the high-level entities that support the business activities of the organization PVFC’s first step in converting to a database approach was to develop a list of the high-level entities that support the business activities of the organization Some of the high-level entities identified at PVFC are the following: CUSTOMER,PRODUCT,EMPLOYEE, Some of the high-level entities identified at PVFC are the following: CUSTOMER,PRODUCT,EMPLOYEE, CUSTOMER ORDER, and DEPARTMENT CUSTOMER ORDER, and DEPARTMENT

22. Chapter 1 © 2005 by Prentice Hall 22 Database approach at PVFC enterprise data model After these high-level entities were identified and defined, the company proceeded to develop an enterprise data model ( graphical model that shows the high-level entities for the organization and associations among those entities) After these high-level entities were identified and defined, the company proceeded to develop an enterprise data model ( graphical model that shows the high-level entities for the organization and associations among those entities)

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24. Chapter 1 © 2005 by Prentice Hall 24 CUSTOMER People and organizations that buy or may potentially buy products from PVFC CUSTOMER People and organizations that buy or may potentially buy products from PVFC ORDER The purchase of one or more products by a customer ORDER The purchase of one or more products by a customer PRODUCT The item PVFC makes and sells PRODUCT The item PVFC makes and sells ORDER LINE Details about each product sold on a particular customer order (such as quantity and price) ORDER LINE Details about each product sold on a particular customer order (such as quantity and price)

25. Chapter 1 © 2005 by Prentice Hall 25 One customer may place many orders, but each order is placed by a single customer  One-to-many relationship

26. Chapter 1 © 2005 by Prentice Hall 26 One order has many order lines; each order line is associated with a single order  One-to-many relationship

27. Chapter 1 © 2005 by Prentice Hall 27 One product can be in many order lines, each order line refers to a single product  One-to-many relationship

28. Chapter 1 © 2005 by Prentice Hall 28 Therefore, one order involves many products and one product is involved in many orders  Many-to-many relationship

29. Chapter 1 © 2005 by Prentice Hall 29 Database approach at PVFC Relational Database After additional data modeling steps (described in Chapter 2) had been completed, the company decided to implement a modern relational database management system that views all data in the form of tables (see Figure 1-5) After additional data modeling steps (described in Chapter 2) had been completed, the company decided to implement a modern relational database management system that views all data in the form of tables (see Figure 1-5)

30. Chapter 1 © 2005 by Prentice Hall 30 Relationships established in special columns that provide links between tables

31. Chapter 1 © 2005 by Prentice Hall 31 Database approach at PVFC Introducing Internet Technology To facilitate the sharing of data and information, PVFC uses a local area network (LAN) that links employee workstations in the various departments to a database server (Figure 1-6) To facilitate the sharing of data and information, PVFC uses a local area network (LAN) that links employee workstations in the various departments to a database server (Figure 1-6) The company mounted a two-phase effort to introduce Internet technology The company mounted a two-phase effort to introduce Internet technology

32. Chapter 1 © 2005 by Prentice Hall 32 Database approach at PVFC Introducing Internet Technology First, to improve intracompany communication and decision making, an intranet was installed that uses Web-based technology and is only accessible from within the company First, to improve intracompany communication and decision making, an intranet was installed that uses Web-based technology and is only accessible from within the company In the second phase, PVFC opened up its intranet to their customers by linking it to the Internet. The Internet connection is configured as an extranet, so that only approved retailers can access the company intranet In the second phase, PVFC opened up its intranet to their customers by linking it to the Internet. The Internet connection is configured as an extranet, so that only approved retailers can access the company intranet

33. Chapter 1 © 2005 by Prentice Hall 33 Client/server system architecture

34. Chapter 1 © 2005 by Prentice Hall 34 Database approach at PVFC A Database Application A database application is an application program (or set of related programs) that is used to perform a series of activities on behalf of database users. Each database application performs some combination of the following basic operations: A database application is an application program (or set of related programs) that is used to perform a series of activities on behalf of database users. Each database application performs some combination of the following basic operations: Create Create Read Read Update Update Delete Delete One of the important database applications at PVFC creates a customer invoice One of the important database applications at PVFC creates a customer invoice

35. Chapter 1 © 2005 by Prentice Hall 35 Application program functions: inserting new data, updating existing data, deleting existing data, reading data for display

36. Chapter 1 © 2005 by Prentice Hall 36 The Range of Database Applications Personal Databases Personal Databases Workgroup Databases Workgroup Databases Department Databases Department Databases Enterprise Databases Enterprise Databases Internet, Intranet, and Extranet Databases Internet, Intranet, and Extranet Databases

37. Chapter 1 © 2005 by Prentice Hall 37 Personal Databases Are designed to support one user Are designed to support one user Have long resided on personal computers (PCs), including laptops Have long resided on personal computers (PCs), including laptops (pricing program that helps the salesperson determine the best combination of quantity and type of items for the customer to order) (pricing program that helps the salesperson determine the best combination of quantity and type of items for the customer to order)

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39. Chapter 1 © 2005 by Prentice Hall 39 Workgroup Databases A workgroup is a relatively small team of people who collaborate on the same project or application or on a group of similar projects or applications A workgroup is a relatively small team of people who collaborate on the same project or application or on a group of similar projects or applications The group needs a database that will track each item as it is developed and allow the data to be easily shared by the team members The group needs a database that will track each item as it is developed and allow the data to be easily shared by the team members

40. Chapter 1 © 2005 by Prentice Hall 40 Figure 1-9 Workgroup database with local area network

41. Chapter 1 © 2005 by Prentice Hall 41 Department Databases A department is a functional unit within an organization (personnel, marketing, manufacturing, and accounting) A department is a functional unit within an organization (personnel, marketing, manufacturing, and accounting) Are designed to support the various functions and activities of a department Are designed to support the various functions and activities of a department

42. Chapter 1 © 2005 by Prentice Hall 42 Enterprise Databases Whose scope is the entire organization or enterprise. Such databases are intended to support organizationwide operations and decision making Whose scope is the entire organization or enterprise. Such databases are intended to support organizationwide operations and decision making An enterprise database does support information needs from many departments An enterprise database does support information needs from many departments

43. Chapter 1 © 2005 by Prentice Hall 43 Enterprise Databases The evolution of enterprise databases has resulted in two major developments: The evolution of enterprise databases has resulted in two major developments: 1. Enterprise resource planning (ERP) systems (are software applications that provide the (are software applications that provide the data necessary for the enterprise to examine and data necessary for the enterprise to examine and manage its activities) manage its activities) 2. Data warehousing implementations (Data warehouse) An integrated decision support database whose content is derived from the various operational databases An integrated decision support database whose content is derived from the various operational databases

44. Chapter 1 © 2005 by Prentice Hall 44 Figure 1-10 An enterprise data warehouse ( large health-care organization)

45. Chapter 1 © 2005 by Prentice Hall 45 Internet, Intranet, and Extranet Databases The most recent change that affects the database environment is the Internet The most recent change that affects the database environment is the Internet For example, customers order their personal computers directly from the computer manufacturers (this requires database support) For example, customers order their personal computers directly from the computer manufacturers (this requires database support)

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49. Chapter 1 © 2005 by Prentice Hall 49 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 Administrators – personnel responsible for maintaining the database Data Administrators – personnel responsible for maintaining the database System Developers – personnel responsible for designing databases and software (systems analysts and programmers) System Developers – personnel responsible for designing databases and software (systems analysts and programmers) End Users – people who use the applications and databases End Users – people who use the applications and databases

50. Chapter 1 © 2005 by Prentice Hall 50 Figure 1-11 Components of the database environment

51. Chapter 1 © 2005 by Prentice Hall 51 Evolution of DB Systems Flat files - 1960s - 1980s Flat files - 1960s - 1980s Hierarchical – 1970s - 1990s Hierarchical – 1970s - 1990s Network – 1970s - 1990s Network – 1970s - 1990s Relational – 1980s - present Relational – 1980s - present Object-oriented – 1990s - present Object-oriented – 1990s - present Object-relational – 1990s - present Object-relational – 1990s - present Data warehousing – 1980s - present Data warehousing – 1980s - present Web-enabled – 1990s - present Web-enabled – 1990s - present