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Class 14: Systems Analysis and Design July 30 th, 2009

 Check your grades  Correct?  Absences  Final  Quizzes  Course evaluation  Handing back assignments  Assignment 4 starts today, is due Thursday  We are having a party!! Next Tuesday!  Giraffe

 List a few current events in information systems news  Compare and contrast four methods for systems analysis and design  Explain what happens in the planning stage  Explain why it is important to understand company culture  Specify requirements by using an event table  Create a context diagram  Create DFD fragments  Create a decision tree

 Buy off-the-shelf products  It’s rare that a single software package serves all of the company’s needs (and future needs!)  Lease the Applications  Better for small to medium-sized companies that might not have the $ to invest in an off-the-shelf product  Use Open Source Software  Quality can be suspect, even though it’s free…  What else is there?

 Pros  Fit / Customization  Modification  Cons  Cost  Risk

Code and fix Iterative and Incremental Development Spiral Model Which one do I choose? Waterfall Model Agile Development

1. Planning Phase 2. Analysis Phase 3. Design Phase 4. Implementation Phase 5. Evaluation Phase 6. Maintenance

 Pros  Cheaper than making changes later in the process  Emphasis on documentation  Big design up front  Simple  Cons  Only effective for non-trivial projects  Inflexible  Might not be aware of future requirements up front

 Pros  Iterative / Flexible  Good for large, expensive and complicated projects  Promotes risk management  Don’t need to know all of the requirements  Cons  Expensive  Slow  Over budget  Over scope

 Pros  Get user feedback early  Understand requirements  Documentation  Cons  Expensive  Slow  Over budget  Over scope

 Pros  Fast  User Involvement  Flexible  Cons  Backtracking  Scope Creep  Cost

 Pros  Not a lot of up-front work  Less Expensive (if you develop the right product)  Cons  Only good for small projects  Wrong product  Doesn’t meet business requirements

1. Planning Phase 2. Analysis Phase 3. Design Phase 4. Implementation Phase 5. Evaluation Phase 6. Maintenance

 1. Define the Problem  2. Produce the Project Schedule***  3. Confirm Project Feasibility  4. Staff the Project  5. Launch the Project *** We’ll do this in our project management lecture

 Understand the Organization  What are the objectives of the organization?  How does the organization work?  How is it run?  What is the organizational culture? Both general culture and major sub-cultures When doing the requirements gathering you will delve more into the details of particular sub-cultures.

 We need a knowledge management system. When employees leave our organization, their knowledge leaves with them. Thus, it feels like our organization is reinventing the wheel every couple of years! We need a system that can capture and document employees knowledge, and then make it possible for future employees to access this documentation. Only managers should be able to delete knowledge. Our IT staff will enter the system to format and organize the data.

 Based on the culture of these two organizations, what differences do you foresee in their associated knowledge management systems in the future?

 Most important part of this phase:  Defining the System Requirements  System Requirements – what the system needs to be able to do in terms of functionality/capabilities!

 We can start to define the system requirements based on events that affect the system.  Events have triggers, sources, use cases, responses, and destinations.

 To decide what kinds of functionality the system needs, we can create an event table. EventTriggerSourceUse CaseResponseDestination Customer wants to check item availability Item inquiryCustomerLook up item availability Item availability details Customer Customer places an order Order inquiry CustomerPlace orderOrder detailsCustomer Time to produce transaction summary reports “End of business day” NoneProduce the reports Reports summary Management

EventTriggerSourceUse CaseResponseDestination An academic department wants to schedule a course Scheduling request Academic Department Schedule a course Class Schedule System A student wants to enroll in a course Enrollment Request StudentEnroll student ScheduleStudent Class lists are distributed to faculty “Beginning of Semester” SystemProduce class list Class ListFaculty

 Employees can post knowledge  Employees can search knowledge  Managers can delete posts  Staff can format posts EventTriggerSourceUse CaseResponseDestination

EventTriggerSourceUse CaseResponseDestination

 We have just looked at events that can be processed by the system.  Now we need to know the procedures of each process we defined as an event.  For this purpose, we will use Data Flow Diagrams.

 A Data Flow Diagram (DFD) is a graphical system model that shows all of the main requirements for an information system in one diagram.  This includes inputs and outputs, processes, and data storage.  Difference between ERD and DFD?

External Agent Data Store 1 Process Data Flow

 There are a few levels of abstraction to note when dealing with DFDs.  The context diagram is the highest level of abstraction. It contains only one process – the system itself – and the external agents that interact with the system.

Faculty Member Academic Department Student Course Registration System Schedule Data Class List Enrollment Request Schedule

 Give your system a name.

Context Diagrams are usually created directly from Event Tables (sources and triggers are shown). The Context Diagram defines the system’s scope.

 We then use the Use Cases defined in the Event Table to create DFD Fragments. Academic Department 1 Schedule Course Course Data Schedule Data

 You will need the external agent, the data flows, process, and data stores. Student 2 Enroll Student Enrollment Request Schedule Enrollment Data Course Data

 You will need the external agent, the data flows, process, and data stores. Faculty Member 3 Produce Class List Class List Enrollment Data Course Data

Faculty Member 3 Produce Class List Class List Enrollment Data Course Data Student 2 Enroll Student Enrollment Request Schedule Enrollment Data Course Data Academic Department 1 Schedule Course Course Data Schedule Data

 Black Hole – data goes into a process and nothing comes out!  Miracle – nothing goes into a process and data comes out! 2 Enroll Student Enrollment Request Course Data Student 2 Enroll Student Schedule Enrollment Data Student

Academic Department 1 Schedule Course Course Data Enrollment Data 3 Produce Class List 2 Enroll Student Student Faculty Member Schedule Data Enrollment Request Schedule Class List

 Diagram 0 contains all DFD fragments. Don’t worry… you won’t be required to perform this feat! But I will show you what one looks like.  Just focus on creating event tables, context diagrams, and DFD fragments.  Rome wasn’t built in a day.

 The Decision Tree is another Systems Analysis tool that summarizes decision logic.

 To decide delivery charge, we look at the following variables:  Purchase Cost  Is it greater or less than $250?  Number of Items Purchased  Is it greater than or equal to four? Or less than or equal to three?  Delivery Day  Is it next day delivery? 2 nd day delivery? Or 7 th day delivery?

Purchase > 250? # items Delivery day NoYes <=3 >=4 <=3>=4 next 2nd 7th 2nd 7th 2nd 7th 2nd 7th DECISION MADE ON DELIVERY COST (in $)

 By looking at the following variables, we can decide whether or not to expedite delivery.  Customer Type  Are they a new customer or not?  Back Order  Is the item on back order more than 25 days or not?  Return Instructions  Are detailed instructions to be included or not?

 More systems analysis and design  We will look at Project Management  This will include the Planning Phase of the SDLC  Cost/Benefit Analysis  Feasibility Analysis  Management techniques, in general