REQUIREMENTS ANALYSIS This repository of slides is intended to support the named chapter. The slide repository should be used as follows: Copy the file to a unique name for your course and unit. Edit the file by deleting those slides you don’t want to cover, editing other slides as appropriate to your course, and adding slides as desired. Print the slides to produce transparency masters or print directly to film or present the slides using a computer image projector. Each slide includes instructor notes. To view those notes in PowerPoint, click-left on the View Menu; then click left on Notes View sub-menu. You may need to scroll down to see the instructor notes. The instructor notes are also available in hardcopy as the Instructor Guide to Accompany Systems Analysis and Design Methods, 6/ed.

Context of System Analysis

Requirements Analysis The process and technique that a group of system analyst utilizes to identify, analyze, and understand system requirements System’s requirements specify what the system must do as well as what property or quality the system must have. One of the early IS development phases. Data Model: one of the primary activities for the requirements analysis phase of the DB System Development No additional notes.

Relative Cost to Fix an Error

Relative Cost to Fix an Error (BASED ON CONSULTANT REPORTS & TRADE LITERATURE) 1 2 3 4 5 COSTS ANALYSIS AND DESIGN PROGRAMMING CONVERSION POSTIMPLELENTATION

Results of Incorrect Requirements Analysis The system may cost more than projected Denver airport Baggage-Handling IS The system may be delivered later than promised. The system may not meet the users’ expectations and that dissatisfaction may cause them not to use it. Once in production, the costs of maintaining and enhancing the system may be excessively high. California DMV system No additional notes.

Very Difficult to Manage Over the lifetime of the project, it is very common for new requirements to emerge and existing requirements to change. Studies have shown that over the life of a project as much as 50 percent or more of the requirements will change before the system is put into production.

System Development is about Documentation……. Data model is part of an official DB document (blue print of the DB) Department of Justice System development is about “documentation….. Documentation…… documentation” See the Department of Justice SDLC documentation on the course website

IS Architecture Can be divided into data and process architectures Data architecture by Data Model ERD: focus on the optimal organization of data, not on where or how data are used Process architecture by Process Model DFD (Data Flow Diagram): focus on how and when data are moved

Information Systems Architecture Data Architecture Process Architecture

How to develop IS Architecture? How the foundation of IS architecture should be developed? Strategic Management Mission statement: root of strategic Mngt. Corporate Strategy IS Strategy IS architecture Data (ERD) and Process (DFD) Architectures

What is Strategic Management? Highest level of overall planning is the continuous planning, monitoring, analysis, and assessment of all that is necessary for an organization to meet its goals & objectives and to position a firm to succeed in its market environment.

Strategic Management Process (con’t) Components of Strategic Management Process Strategic Management Process (4:35)

What is Data Flow Diagram? A DFD is a graphical representation of the "flow" of data through an information system. How data enter a system and transformed in that system What is a Data Flow Diagram and Why Do You Need One? (2:28)

Creating Data Flow Diagram Lemonade Stand Example

Creating Data Flow Diagrams Example Steps: The operations of a simple lemonade stand will be used to demonstrate the creation of data flow diagram. Create a list of activities Construct Context Level DFD (identifies sources and sink) Construct Level 0 DFD (identifies manageable sub processes ) Construct Level 1- n DFD (identifies actual data flows and data stores )

Creating Data Flow Diagrams Example Create a list of activities Think through the activities that take place at a lemonade stand. Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor

Creating Data Flow Diagrams Example Construct Context Level DFD (identifies sources and sink) Create a context level diagram identifying the sources and sinks (users). Context Level DFD Sales Forecast CUSTOMER 0.0 Lemonade System EMPLOYEE Order Production Schedule Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor Product Served Pay Payment Time Worked Received Goods Payment Purchase Order VENDOR

Creating Data Flow Diagrams Example Construct Level 0 DFD (identifies manageable sub processes ) Create a level 0 diagram identifying the logical subsystems that may exist. Level 0 DFD 1.0 Sale Sales Forecast Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor Customer Order Product Ordered CUSTOMER Payment 2.0 Production EMPLOYEE Production Schedule Product Served Inventory Received Goods VENDOR 3.0 Procure-ment Purchase Order Order Decisions Payment Pay Time Worked 4.0 Payroll

Creating Data Flow Diagrams Example Construct Level 1- n DFD (identifies actual data flows and data stores ) Create a level 1 decomposing the processes in level 0 and identifying data stores. Level 1 DFD CUSTOMER Customer Order Request for Forecast Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor ORDER 1.1 Record Order 1.3 Produce Sales Forecast Severed Order Payment Sales Forecast 1.2 Receive Payment PAYMENT

Process Decomposition 1.0 Sale 1.1 Record Order 1.2 Receive Payment 2.0 Production 2.1 Serve Product 2.2 Produce Product 2.3 Store Product 0.0 Lemonade System 3.0 Procure-ment 3.1 Produce Purchase Order 3.2 Receive Items 3.3 Pay Vendor 4.0 Payroll 4.1 Record Time Worked 4.2 Calculate Payroll 4.3 Pay Employee Context Level Level 0 Level 1

Why not using Flow Chart? Complex Logic: Many of today’s MIS program logic is quite complicated. In that case, flowchart becomes complex and clumsy because the complexity can grow exponentially. Not so recommendable in MIS & CS Alterations and Modifications: If alterations are required the flowchart may require re-drawing completely. This is quite time and effort-consuming.

Why not using Flow Chart? Reproduction: As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem. The essentials of what is done can easily be lost in the technical details of how it is done. Factors that affect the sequence are not included.