Chapter 1 the database environment


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Chapter 1 the database environment

  1. 1. Chapter 1:The Database Environment Modern Database Management 7th EditionMELJUN CORTES 1
  2. 2. Definitions Data: stored representations of meaningful objects and events  Structured: numbers, text, dates  Unstructured: images, video, documents Information: data processed to increase knowledge in the person using the data Metadata: data that describes the properties and context of user data Database: organized collection of logically related dataChapter 1 2
  3. 3. Figure 1-1a Data in context Context helps users understand dataChapter 1 3
  4. 4. Figure 1-1b Summarized data Graphical displays turn data into useful information that managers can use for decision making and interpretationChapter 1 4
  5. 5. Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and data contextChapter 1 5
  6. 6. Disadvantages of File Processing Program-Data Dependence  All programs maintain metadata for each file they use  File descriptions are stored within each application program that accesses a given file Duplication of Data  Different systems/programs have separate copies of the same data Limited Data Sharing  No centralized control of data Lengthy Development Times  Programmers must design their own file formats Excessive Program Maintenance  80% of information systems budget Chapter 1 6
  7. 7. Figure 1-3 Old file processing systems at Pine Valley Furniture Company Duplicate DataChapter 1 7
  8. 8. Problems with Data Redundancy Waste of space to have duplicate data Causes more maintenance headaches The biggest problem:  Data changes in one file could cause inconsistencies  Compromises in data integrityChapter 1 8
  9. 9. SOLUTION: The DATABASE Approach  Central repository of shared data  Data is managed by a controlling agent  Stored in a standardized, convenient form Requires a Database Management System (DBMS)Chapter 1 9
  10. 10. Database Management System  A software system that is used to create, maintain, and provide controlled access to user databases Order Filing System Invoicing Central database DBMS System Contains employee, order, inventory, pricing, and Payroll customer data SystemDBMS manages data resources like an operating system manages hardwareresources Chapter 1 10
  11. 11. Advantages of the Database Approach  Program-data independence - The separation of data descriptions (metadata) from the application programs that use the data  Planned data redundancy  Improved data consistency  Improved data sharing  Increased application development productivity  Enforcement of standards  Improved data quality  Constraint – rule that cannot be violated by database users Chapter 1 11
  12. 12. Advantages of the Database Approach  Improved data accessibility and responsiveness  Reduced program maintenance  Improved decision support Chapter 1 12
  13. 13. Costs and Risks of the DatabaseApproach  New, specialized personnel  Installation and management cost and complexity  Conversion costs  Legacy system refers to older applications in an organization  Need for explicit backup and recovery  Organizational conflict Chapter 1 13
  14. 14. Figure 1-5 Components of the Database EnvironmentChapter 1 14
  15. 15. Components of the Database Environment CASE Tools–computer-aided software engineering  Automated tools used to design databases and application programs Repository–centralized storehouse of metadata Database Management System (DBMS) –software for managing the database Database–storehouse of the data Application Programs–software using the data User Interface–text and graphical displays to users Data/Database Administrators–personnel responsible for maintaining the database System Developers–personnel responsible for designing databases and software End Users–people who use the applications and databasesChapter 1 15
  16. 16. The Range of Database Applications  Personal databases  Workgroup databases  Departmental/divisional databases  Enterprise database Chapter 1 16
  17. 17. Figure 1-6 Typical data from a personal databaseChapter 1 17
  18. 18. Figure 1-7 Workgroup database with wireless local area networkChapter 1 18
  19. 19. Figure 1-8 An enterprise data warehouseChapter 1 19
  20. 20. Chapter 1 20
  21. 21.  Extranet – use of internet protocols to establish limited access to company data and information by the company’s customers and suppliers. Intranet – use of internet protocols to establish access to company data and information that is limited to the organization.Chapter 1 21