DB Design Methodology 1 A Database Design Methodology Area of application Design of database with its applications Perspective The method assumes that the primary purpose of the future system is to automate current or planned activities of the enterprise The method assumes as do all database design methodologies that different views on the enterprise conflicts and political differences will be resolved during the database design process Life Cycle The life cycle comprises the following steps Project Progress Report Phase I g I 1 Environment Requirement Analysis g I 2 System Analysis Specification Project Progress Report Phase II g II 1 Conceptual Modeling g II 2 Logical Modeling g II 3 Task Emulation g II 4 Optimization NOT REQUIRED for the 424 project Project Progress Report Phase III g III Implementation g III 1 Convert Emulated tasks to code g III 2 Bulk Loading Tuning LIMITED for the 424 project g III 3 Testing Limitation The methodology does not cover implementation testing maintenance and project management DB Design Methodology 2 Example Design a Merryland State Motor Vehicle Administration MVA Information System The system must support all activities of the Merryland State MVA The tasks of the MVA include maintaining all information pertaining to vehicle emissions license maintenance vehicle registration maintenance fine and fee maintenance driving record maintenance and report generation Etc etc DB Design Methodology 3 I 1 Environment Requirements Analysis The purpose of this phase is to investigate the information needs of and the activities within the enterprise and determine the boundary of the design problem not necessarily identical to the boundary of the future computerized system if any Input Information describing the current status of the enterprise possible inefficiencies plans for the future and constraints that have to be satisfied in conducting business Output A Top Level Information Flow Diagram describing the major documents and functions and the boundary of the design problem The documents include the major input output and internal documents The functions model the major activities within the enterprise Function To collect the information about the enterprise and design the top level information flow diagram DB Design Methodology 4 Guidelines g Techniques collect information by contacting interviews of people at all levels of the organization analyze questionnaires review short and long term plans business manuals files forms etc Tools express a top level information flow diagram to capture the functions and important documents of the enterprise and to start the design with the i o documents and work from the outside in towards a top level design The tool we use for designing the top level information flow diagram is the following graphic formalism for representing structures and processes structure process information flow g g Two structures are never directly connected Two processes are never directly connected DB Design Methodology 5 MVA Top Level Information Flow Diagram VQE Vehicle Report Request ETT VRE Vehicle Report RAE Registration Application RRE Reg Renewal Notice OWI Owner Information RMT Registration Maintenance FSE Fee Schedule Report VHI Vehicle Information LMT License Maintenance PRI Payment Information RCE Registration Card TSE Tag and Sticker ETE Emmisions Test Notice Emmissions Testing FSI Fee Schedule FFT LRE Lic Renewal Notice LIE Driver s License PEI Personal Information MBE Monthly Bad Records UFI Unpaid Fine Information Fine and Fee Maintenance LAE License Application DLI Driver License Information RPT Reports LPE Late Payment Notice MAE Monthly Accounting YSE Yearly Statistics VSI Violation Schedule FPE Fine Payment DRT Driving Record Maintenance DRI Driver Record Information FCE Fee Change Request VCE Violat Change Request RQE Driving Record Request DRE Driving Record Report CTE Violation Citation PWE Points Warning DB Design Methodology 6 I 2 System Analysis Specification The purpose is to divide the functions from the Top Level Information Flow Diagram hierarchically into tasks The tasks should be reasonably independent to minimize the task to task interfaces documents During the division process the documents used by each function are also broken down The process is continued until each task is small enough to be clearly understood and until each document can be conveniently expressed in terms of data elements that cannot be further divided The result is a detailed Task Flow Diagram and a set of forms describing the documents and the tasks Input The Top Level Information Flow Diagram and information about the documents and functions from phase 1 Output Task Forms Document Forms Document and Data Usage Matrices and the detailed Task Flow Diagram Function Decompose functions and documents Specify the resulting Task and component Document Forms Specify Document and Data Usage Matrices Design detailed Task Flow Diagram Guidelines g Technique top down hierarchical decomposition g Tools Task Forms Document Forms Usage Matrices and the graphical formalism for Task Flow Diagrams DB Design Methodology 7 Examples of Task Forms TASK NUMBER TASK NAME PERFORMER PURPOSE ENABLING COND DESCRIPTION FREQUENCY DURATION IMPORTANCE MAXIMUM DELAY INPUT OUTPUT DOCUMENT USE OPS PERFORMED SUBTASKS ERROR COND LMT License Maintenance Driver registration staff Maintain all driver licensing information Receipt of License Application LAE Receipt of License Renewal Notice LRE First day of each month Last day of each month Issue new licenses and process renewals Print renewal notices on a monthly basis Delete expired licenses on a monthly basis See subtasks different for each subtask See subtasks different for each subtask See subtasks different for each subtask See subtasks different for each subtask DLI Driver License Infor FSI Fee Schedule LAE License Application LRE License Renewal Notice PEI Person Info DLI Driver License Info ENE Expiration Notice LIE Driver s License LRE License Renewal Notice PEI Person Info PRI Payment Record DLI all columns LIE all columns LAE all columns PEI all columns FSI all columns PRI all columns LRE all columns ENE all columns See subtasks LMT 1 NEW LICENSE LMT 2 RENEWLICENSE LMT 3 PRINT RENEWALNOTICES LMT 4 DELETE EXPIRATIONS See subtasks DB Design Methodology 8 Examples of Task Forms TASK NUMBER TASK NAME PERFORMER PURPOSE ENABLING COND DESCRIPTION FREQUENCY DURATION IMPORTANCE MAXIMUM DELAY INPUT OUTPUT DOCUMENT USE
View Full Document
Unlocking...