IS CH2 Database Management (p1)

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IS CH2 Database Management (p1)

  1. 1. INFORMATION SYSTEMS<br />DATABASE MANAGEMENT (PART 1)<br />Prepared by: Jan Wong<br />
  2. 2. The Learning Outcomes<br />Understand what are DATABASES<br />Identify the components of a database<br />Explain why data is importantto an organization<br />Understand file maintenance techniques<br />File processing System VS Database System<br />
  3. 3. The Keywords<br /><ul><li>Database
  4. 4. Data Integrity
  5. 5. GIGO
  6. 6. Data Hierarchy
  7. 7. Data Types
  8. 8. Validation
  9. 9. File Processing System
  10. 10. Database Processing System
  11. 11. Procedure
  12. 12. Data Dictionary
  13. 13. Report Generator</li></li></ul><li>Data & Information<br />How are Data and Information Related?<br />Example:<br />Student ID<br />
  14. 14. Data & Information<br />What is Data Integrity?<br />Degree of which data is correct<br />Garbage in, Garbage out (GIGO) - cannot create correct information from incorrect data<br />
  15. 15. Data & Information<br />What are the qualities of Valuable Information?<br />6 Qualities:<br />Accurate<br />Verifiable<br />Timely<br />Organized<br />Meaningful<br />Cost Effective<br />+ 1: Accessible<br />
  16. 16. Data & Information<br />What is a database?<br /><ul><li>Collection of data, organized so you can access, retrieve and use it</li></ul>Database Software (DBMS)<br />Database Management System <br /> (e.g. Access, Oracle, MySQL, MS SQL)<br /><ul><li>Create database
  17. 17. Add, Change (edit) & Delete Data
  18. 18. Sort & Retrieve Data
  19. 19. Create Forms & Reports</li></ul>DATABASE<br />
  20. 20. Data Hierarchy<br />FIELDS<br />RECORDS<br />U<br />C<br />FILES<br />D<br />1<br />F<br />CHARACTERS<br />DATABASE<br />1<br />1<br />
  21. 21. In other words…<br />DATABASE<br />
  22. 22. Data Hierarchy<br />What is are fields?<br /><ul><li>Combination of one or more characters
  23. 23. Smallest unit of data a user can access to
  24. 24. Field Name: Uniquely identifies each field
  25. 25. Field Size: Defines the maximum number of characters the field can contain
  26. 26. Data Type: Specifies what kind of data the field contains</li></ul>FIELDS<br />
  27. 27. Data Hierarchy: Data Types<br />Text<br />Memo<br /><ul><li>Also called AlphaNumeric
  28. 28. Letters, numbers & special characters
  29. 29. Lengthy alphanumeric entries</li></ul>Numeric<br /><ul><li>Numbers only</li></ul>Yes/No<br /><ul><li>Also called Boolean
  30. 30. Only for values ‘Yes’ / ‘No’ or ‘True’ / ‘False’</li></ul>AutoNumber<br /><ul><li>Unique number automatically assigned to each new record</li></ul>Hyperlink<br /><ul><li>Web address that links to document or web page</li></ul>Currency<br /><ul><li>Currency
  31. 31. Numbers with decimal values</li></ul>Object<br /><ul><li>Also called BLOB (binary large object)
  32. 32. Photograph, audio, video, or any external file</li></ul>Date<br /><ul><li>Month, day, year and time</li></li></ul><li>Data Hierarchy<br />What is are records?<br /><ul><li>Group of related fields
  33. 33. How to uniquely differentiate records?</li></ul>Primary Key<br />RECORD<br />
  34. 34. Data Hierarchy<br />What is are data files?<br />Collection of related records stored on disk<br />FILE<br />
  35. 35. IN-CLASS ACTIVITY<br />Get into groups of 5-6<br />Select an Information System as below:<br /><ul><li>Library Management System
  36. 36. Lecturer Management System
  37. 37. Ticket Reservation System (e.g. Cinema)
  38. 38. Inventory Management System (e.g. Hypermarkets)</li></ul>List down the contents within it’s database<br /><ul><li>Files, Records and Fields</li></li></ul><li>Maintaining Data<br />What is file maintenance?<br /><ul><li>Procedures that keep data current / updated</li></ul>Adding records<br /><ul><li>When there is new data</li></ul>Changing / Editing records<br /><ul><li>Correct incorrect data
  39. 39. Update of old data</li></ul>Deleting records<br /><ul><li>When records are no longer needed
  40. 40. Some programs totally deletes record, some merely ‘flags’ them</li></li></ul><li>Maintaining Data<br />What is Data Validation?<br />Process of comparing data with a set of rules to find out if data is correct<br />Reduce data entry errors, duplicates and enhance data integrity before program writes data on disk<br />
  41. 41. File Processing System<br />Each department has it’s own set of files<br />Records in one file may not relate to records in another file<br /> e.g. HR dept & other depts<br />Possible weaknesses:<br />Data redundancy: Same fields / records stored in different files<br />Isolated data: Data stored in different files therefore difficult to access<br />
  42. 42. DatabaseProcessing System<br />Many programs and users can share data in database<br />Secures data so only authorized users can access certain data<br />Strengths:<br /> Reduced data redundancy<br /> Improved data integrity<br /> Shared data<br /> Faster / Centralized Access<br /> Reduced development time<br />
  43. 43. “Assists organizations / ‘people’ in creating and managing databases”<br />Database ManagementSystems (DBMS)<br />
  44. 44. “Data Dictionary - Contains data about each file in database and each field within those files”<br />Database ManagementSystems (DBMS)<br />
  45. 45. “Report Generator - Allows user to design a report on screen, retrieve data into report design, then display or print reports”<br />Database ManagementSystems (DBMS)<br />
  46. 46. What is the difference between Backup & Log:<br />Backup – Copy of the entire database<br />Log – Listing of activities that change database content<br /> DBMS usually logs 3 items:<br /><ul><li>Before Image
  47. 47. Actual Change
  48. 48. After Image</li></ul>Database ManagementSystems (DBMS)<br />
  49. 49. Questions, anyone?<br />
  50. 50. Chapter 2: Database Management (Part 2)<br />

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