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Database management systems cs403 power point slides lecture 05
- 1. © Virtual University of Pakistan Database Management Systems Lecture - 5
- 2. © Virtual University of Pakistan Lecture’s Overview Database Application Development Process Preliminary Study of System
- 3. © Virtual University of Pakistan Database Application Development Process Involves Database Design Application Programs Implementation
- 4. © Virtual University of Pakistan Database Design A DB Design is a model of a particular real-world system It provides a picture of reality Should be simple and self- explanatory
- 5. © Virtual University of Pakistan Database Development Process
- 6. © Virtual University of Pakistan Database Development Process Similar to software development process Preliminary Study Requirement Analysis DB Design Physical Design Implementation Maintenance
- 7. © Virtual University of Pakistan Design Stages Analyze User Environment Develop Conceptual Model Map Conceptual Model to Logical Choose DBMS Develop Physical Design Implement System Test System Operational Maintenance
- 8. © Virtual University of Pakistan Analyze Existing System Objective: To understand the working of existing system Analyze users’ requirements
- 9. © Virtual University of Pakistan Tool Used Why to use at all? Data Flow Diagrams
- 10. © Virtual University of Pakistan Data Flow Diagrams
- 11. © Virtual University of Pakistan Data Flow Diagrams (DFDs) Represent the flow of dataflow of data between different processesbetween different processes within a systemwithin a system
- 12. © Virtual University of Pakistan Data Flow Diagrams Simple & intuitive, not focusing on details To describe, what users dowhat users do, rather than what computers do
- 13. © Virtual University of Pakistan Data Flow Diagrams Limitations Focus only on flows of information Decision points/basis not included
- 14. © Virtual University of Pakistan DFD-Symbols Dataflows: pipelines through which packets of information flow. Arrows are labeled with name of the data that moves through
- 15. © Virtual University of Pakistan DFD-Symbols Data Store Repositories of data in system Static data Data held for processing Name is a noun phrase
- 16. © Virtual University of Pakistan DFD-Symbols Process transforms incoming data flow into outgoing data flow OR
- 17. © Virtual University of Pakistan DFD-Process Numbered Name is verb/object phrase; Noun for high-level systems OR 1.0 Process 1.0 Process
- 18. © Virtual University of Pakistan DFD-Symbols External Entities Sources/destinations for data Outside the system Name is Noun Phrase
- 19. © Virtual University of Pakistan DFD-Symbols Collector Several data flows combine here No processing occurs here
- 20. © Virtual University of Pakistan DFD-Symbols Separator Several data flows split from here No processing
- 21. © Virtual University of Pakistan DFD-Symbols Ring-sum operator Shows two possible data flows Only one is followed
- 22. © Virtual University of Pakistan DFD-Symbols AND operator Shows two data flows Both are followed
- 23. © Virtual University of Pakistan Types of DFD Context diagram Level 0 diagram Detailed diagram
- 24. © Virtual University of Pakistan Context Diagram Consists of single Process/System Represents the system/process being analyzed Name: Usually a Noun phrase
- 25. © Virtual University of Pakistan Context Diagram Show Context Only Inputs/outputs External Entities No Data Stores No flows between external entities
- 26. © Virtual University of Pakistan Context Diagram
- 27. © Virtual University of Pakistan Context Diagram Registrar Dean Student Faculty Member Class Requests Schedule Student Data Course Offerings Class Counts Faculty Load Sheets Class Lists Admission System
- 28. © Virtual University of Pakistan Diagram 0 1.0 Process Requests 3.0 Create Student File 4.0 Create Class File 7.0 Produce Faculty Load Sheets Registrar Student Faculty member Dean Class Registration C 2.0 Produce Student Schedule Class Requests Request Status Old Class Data Updated Class Data Updated Student Data Student Registration S 6.0 Produce Class Counts 5.0 Produce Class Lists Student Data Course Offering
- 29. © Virtual University of Pakistan That is all for lecture 5, however, Due to time available discussed Level 0 diagram in air, to be included Later inshAllah
- 30. © Virtual University of Pakistan
- 31. © Virtual University of Pakistan Registrar Dean Student Faculty Member Class Requests Schedule Student Data Course Offerings Class Counts Faculty Load Sheets Class Lists Admission System
- 32. © Virtual University of Pakistan
- 33. © Virtual University of Pakistan Diagram 0 1.1 Process Requests 3.0 Create Student File 4.0 Create Class File 7.0 Produce Faculty Load Sheets Registrar Student Faculty member Dean Class Registration C 2.0 Produce Student Schedule Class Requests Invalid Request Old Class Data Updated Class Data Updated Student Data Student Registration S 6.0 Produce Class Counts 5.0 Produce Class Lists Student Data Course Offering
- 34. © Virtual University of Pakistan Detailed Diagram Student Class Requests Invalid Request 1.1 Edit Requests 1.2 Check Class Counts Valid Requests Class Registration C 1.4 Update Class Data UpdatedClassData O ld Class Data Accepted Request 1.3 Update Student Data Student Registration S Accepted Request Rejected Request
- 35. © Virtual University of Pakistan
- 36. © Virtual University of Pakistan Overview Continue discussion on DFD Discussion on Design Phase Database Design and Data Models
- 37. © Virtual University of Pakistan Database Management Systems Lecture - 5