Revised by Ivor Perry Sept From Flow Charts to UML - 1

Revised by Ivor Perry Sept Agenda Process Analysis and Modelling Rich Picture Manual Flowchart Data Dictionaries

Revised by Ivor Perry Sept Process Analysis and Modelling Most approaches are structured - why? To answer the following questions Why is an information system being developed? How should it be developed - the process? How can this process be managed - the project? What is the best way to set down this knowledge? What is the best way to teach or pass on this knowledge?

Revised by Ivor Perry Sept Coming Up Fast! The Commonest Approach Hard and Soft Approaches Soft e.g. Soft Systems Methodology (SSM) - Checkland –Emphasis on human and organisational perspective Hard e.g. SSADM, DSDM –focus on processes and transactions entities about which data is stored Object Orientation (OO) approach e.g. Unified Modelling Language (UML) –seeks to bring together process and data –an object will have attributes, but also services (e.g. procedures, functions) Curtis & Cobham Ch 16

Revised by Ivor Perry Sept Using Graphical Tools Easier for users to understand Demonstrate processes and business rules consistently May show business rules more clearly (ERD) May show process bottlenecks (Manual Flowchart) Assist in defining boundaries (Rich Picture, ERD) Useful in preventing ‘scope creep’

Revised by Ivor Perry Sept Understanding the task -the Rich Picture Courses Bookings Casual staff Permanent staff Customers Suppliers Health & Safety enquiries Rooms & courts book watches deliver order ? Curtis & Cobham Ch 16

Revised by Ivor Perry Sept The Rich Picture Focusses attention on the important issues Helps people to visualise and discuss their roles Is used to define the boundaries of the project Represents 3 important elements in systems design Elements of structure –boundaries, physical layout, products and services Elements of process –what happens Elements of relationships –the relationship between structure and process Curtis & Cobham Ch 16

Revised by Ivor Perry Sept The Data Dictionary A store of data about data It holds the name of the data element the type of data it is the structure, e.g. for a flow or store, the aggregates or data items which comprise it the usage characteristics, e.g. the processes a flow interacts with, or the aggregates which use a data item. Curtis & Cobham Ch 10

Revised by Ivor Perry Sept Manual Flowcharts Considers the physical processes Usually used to record flow of documents in a manual system Use commonly agreed symbols NOT a system design –would simply lead to replicating the manual system Curtis & Cobham Ch 10

Revised by Ivor Perry Sept Manual Flowcharts Claim form Validate policy Docs in suspense file OK? Check against terms Garage report No - refuse claim Yes- raise cheque letter Motor Insurance Claim Policy OK? Garage Request inspection fax Yes Confirmation letter Yes Rejection letter No Curtis & Cobham Ch 10

Revised by Ivor Perry Sept Manual Flowcharts - Summary Advantages Easier to understand than narrative Preparing a chart means the analyst has to understand the process Incompleteness of the process is easily discovered Little technical knowledge is required to understand a chart Weaknesses in the system are shown up, e.g. bottlenecks, duplication of work etc. Curtis & Cobham Ch 10

Revised by Ivor Perry Sept Manual Flowcharts - Summary Disadvantages With complex systems flowcharts become unwieldy Difficult to amend Flowchart does not show informal information flows Curtis & Cobham Ch 10

Revised by Ivor Perry Sept End of Lecture