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MIS Jump start!. http://www.youtube.com/watch?v=cL9Wu2kWwSY. MIS 111: Computers and the inter-networked society. Class 14: Systems Analysis and Design July 30 th , 2009. Adminsitration. Check your grades Correct? Absences Final Quizzes Course evaluation Handing back assignments
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MIS Jump start! http://www.youtube.com/watch?v=cL9Wu2kWwSY
MIS 111: Computers and the inter-networked society Class 14: Systems Analysis and Design July 30th, 2009
Adminsitration • 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
Learning Objectives • 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
Information Systems solutions • 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?
Developing Applications In-House • Pros • Fit / Customization • Modification • Cons • Cost • Risk
Statistically speaking, This could be your project(62% of IT projects fail)
several frameworks to follow Spiral Model Waterfall Model Iterative and Incremental Development Agile Development Which one do I choose? Code and fix
General steps in the software development Life cycle • Planning Phase • Analysis Phase • Design Phase • Implementation Phase • Evaluation Phase • Maintenance
Waterfall model • 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
Spiral model • 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
Iterative and Incremental Development • Pros • Get user feedback early • Understand requirements • Documentation • Cons • Expensive • Slow • Over budget • Over scope
Iterative and Incremental Development • Pros • Fast • User Involvement • Flexible • Cons • Backtracking • Scope Creep • Cost
Iterative and Incremental Development • 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
General steps in the software development Life cycle • Planning Phase • Analysis Phase • Design Phase • Implementation Phase • Evaluation Phase • Maintenance
The planning phase • 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
Define a problem statement • 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.
Consider this request: • 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.
What would you do? • Based on the culture of these two organizations, what differences do you foresee in their associated knowledge management systems in the future?
The analysis phase • 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!
Defining system requirements • We can start to define the system requirements based on events that affect the system. • Events have triggers, sources, use cases, responses, and destinations.
System requirements analysis • To decide what kinds of functionality the system needs, we can create an event table.
You try this event table – Knowledge management • Employees can post knowledge • Employees can search knowledge • Managers can delete posts • Staff can format posts
System requirements analysis • 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.
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?
Some new symbols (yes!!!) External Agent Data Store 1 Process Data Flow
Levels of abstraction • 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.
Context diagram Academic Department Schedule Data Enrollment Request Course Registration System Faculty Member Student Schedule Class List
You try: Context diagram • 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.
Dfd fragments • We then use the Use Cases defined in the Event Table to create DFD Fragments. 1 Schedule Course Academic Department Course Data Schedule Data
enroll student • You will need the external agent, the data flows, process, and data stores. Enrollment Request 2 Enroll Student Student Enrollment Data Course Data Schedule
Produce class list • You will need the external agent, the data flows, process, and data stores. 3 Produce Class List Faculty Member Enrollment Data Class List Course Data
1 Schedule Course Academic Department Schedule Data Course Data Enrollment Request 2 Enroll Student Student Enrollment Data Course Data Schedule 3 Produce Class List Faculty Member Enrollment Data Class List Course Data