IS CH2 Database Management (p1)
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The document discusses key concepts related to database management including: 1. It defines databases as collections of organized data that can be accessed, retrieved, and used via database management software. 2. Databases contain fields, records, files, and data types which are the basic units that make up a database. 3. Maintaining accurate and up-to-date data is important, and database management systems help ensure data integrity through validation, adding/editing/deleting records, and reducing redundancy. 4. Database systems improve upon file processing systems by allowing many users and programs to securely share centralized data.
IS CH2 Database Management (p1)
- 1. INFORMATION SYSTEMSDATABASE MANAGEMENT (PART 1)Prepared by: Jan Wong
- 2. The Learning OutcomesUnderstand what are DATABASESIdentify the components of a databaseExplain why data is importantto an organizationUnderstand file maintenance techniquesFile processing System VS Database System
- 5. GIGO
- 7. Data Types
- 8. Validation
- 11. Procedure
- 12. Data Dictionary
- 13. Report GeneratorData & InformationHow are Data and Information Related?Example:Student ID
- 14. Data & InformationWhat is Data Integrity?Degree of which data is correctGarbage in, Garbage out (GIGO) - cannot create correct information from incorrect data
- 15. Data & InformationWhat are the qualities of Valuable Information?6 Qualities:AccurateVerifiableTimelyOrganizedMeaningfulCost Effective+ 1: Accessible
- 16. Data & InformationWhat is a database?Collection of data, organized so you can access, retrieve and use itDatabase Software (DBMS)Database Management System (e.g. Access, Oracle, MySQL, MS SQL)Create database
- 17. Add, Change (edit) & Delete Data
- 18. Sort & Retrieve Data
- 19. Create Forms & ReportsDATABASE
- 22. Data HierarchyWhat is are fields?Combination of one or more characters
- 23. Smallest unit of data a user can access to
- 24. Field Name: Uniquely identifies each field
- 25. Field Size: Defines the maximum number of characters the field can contain
- 26. Data Type: Specifies what kind of data the field containsFIELDS
- 27. Data Hierarchy: Data TypesTextMemoAlso called AlphaNumeric
- 28. Letters, numbers & special characters
- 29. Lengthy alphanumeric entriesNumericNumbers onlyYes/NoAlso called Boolean
- 30. Only for values ‘Yes’ / ‘No’ or ‘True’ / ‘False’AutoNumberUnique number automatically assigned to each new recordHyperlinkWeb address that links to document or web pageCurrencyCurrency
- 31. Numbers with decimal valuesObjectAlso called BLOB (binary large object)
- 32. Photograph, audio, video, or any external fileDateMonth, day, year and timeData HierarchyWhat is are records?Group of related fields
- 33. How to uniquely differentiate records?Primary KeyRECORD
- 34. Data HierarchyWhat is are data files?Collection of related records stored on diskFILE
- 35. IN-CLASS ACTIVITYGet into groups of 5-6Select an Information System as below:Library Management System
- 37. Ticket Reservation System (e.g. Cinema)
- 38. Inventory Management System (e.g. Hypermarkets)List down the contents within it’s databaseFiles, Records and FieldsMaintaining DataWhat is file maintenance?Procedures that keep data current / updatedAdding recordsWhen there is new dataChanging / Editing recordsCorrect incorrect data
- 39. Update of old dataDeleting recordsWhen records are no longer needed
- 40. Some programs totally deletes record, some merely ‘flags’ themMaintaining DataWhat is Data Validation?Process of comparing data with a set of rules to find out if data is correctReduce data entry errors, duplicates and enhance data integrity before program writes data on disk
- 41. File Processing SystemEach department has it’s own set of filesRecords in one file may not relate to records in another file e.g. HR dept & other deptsPossible weaknesses:Data redundancy: Same fields / records stored in different filesIsolated data: Data stored in different files therefore difficult to access
- 42. DatabaseProcessing SystemMany programs and users can share data in databaseSecures data so only authorized users can access certain dataStrengths: Reduced data redundancy Improved data integrity Shared data Faster / Centralized Access Reduced development time
- 43. “Assists organizations / ‘people’ in creating and managing databases”Database ManagementSystems (DBMS)
- 44. “Data Dictionary - Contains data about each file in database and each field within those files”Database ManagementSystems (DBMS)
- 45. “Report Generator - Allows user to design a report on screen, retrieve data into report design, then display or print reports”Database ManagementSystems (DBMS)
- 46. What is the difference between Backup & Log:Backup – Copy of the entire databaseLog – Listing of activities that change database content DBMS usually logs 3 items:Before Image
- 47. Actual Change
- 48. After ImageDatabase ManagementSystems (DBMS)
- 50. Chapter 2: Database Management (Part 2)