IS2210: Systems Analysis and Systems Design and Change Twitter: Website:

Tutorials O Location: O’Rahilly Building (ORB) B.05 O Start Date: Thursday 10/10/2013 (bi- weekly) O Time: 5-6pm

Last Week… O From todays lesson you should… O Understand what constitutes an information system O Know the major role of Information Systems (IS) O Understand Analysis and Design

Questions O What is the difference between data and information? O What are the five components of an information systems? O What is the difference between analysis and design?

Knowledge

Learning Outcomes O From todays lecture you should: O Understand what SDLC is O Understand the five stages of SDLC O Understand the key deliverables of these five stages

Why Systems Development? O Competition can lead to change To improve existing system Outside group may mandate change To correct problem in existing system

How It Can Go… O The next few slides are an exaggerated way systems development can go O However these are not unusual issues O How can we change that?

“ Tree Swing – hanging from branch which people can sit and swing on” “Swing from tree hanging from tree branches which people can sit on” “Seat hanging from tree branches”

Seat which hangs from a tree Comfortable and brilliant tree swing

Obviously no documentation Only partial instalment Budgets overranWas it required?

O Customers may not fully know what they want. Tyre Swing 1.Important to ask the correct questions!! - Errors and omissions can be costly. 2.Follow SDLC to ensure the correct steps are undertaken 3.Communication

Guidelines for System Development O Arrange tasks into phases (groups of activities) O Involve users (anyone for whom the system is being built) O Develop clearly defined standards (procedures the company expects employees to follow)

Systems Development Lifecycle (SDLC) O A process that can be applied to create, or alter information systems O Consists of different models and methodologies that people use to develop/alter IS O It can be seen as a very structured, and methodological way of developing IS

Emergence of SDLC O Winston Boyce conceived SDLC as an aid to programming, with two stages of analysis and coding in 1970 O Further to this, Dr. Barry Boehm listed a number of the main phases of software development in 1974

What It TRIES To Do… O It tries to ease the process of building a system O It tries to help reduce failures like unclear objectives, cost overruns, etc. O It tries to reduce the possibility of a system not meeting user needs

SDLC Phases

Phase 1: Planning O Initial phase of any SDLC O We initially would receive a request from the user for systems development O We do NOT just go and build it!!!

Planning Stages: O Identify the problem to be solved by investigating the issue O Establish a team O Develop appropriate documentation O Project Charter (scope, objectives, participants) O Business Case O Project Feasibility (legally, technically, economically)

Key Deliverables O General Problem Statement O Team members and roles O Feasibility Report

Phase 2: Analysis O Analysis: System requirements are studied and structured O This is achieved by asking questions such as: O Why do problems exist? O Why were certain methods of work adopted? O Are there alternative methods?

Analysis Stages: O Study and analyse the current system O System analysts collect facts from existing users O Existing systems limitations and details O Define new system objectives

O Define and Prioritise Users Requirements O The analyst approaches the users to find out what they want from the system O They use different data gathering techniques such as interviews, observations, and surveys O This is an attempt to understand all aspects of the current system and eventually indicate how things may be improved by a new system

Key Deliverables O Formal requirements document (business requirements statement) O Data Flow Diagram (DFD) and Entity Relationship Diagram (ERD) of current system

Phase 3: Design O System Design: Describes how the system will fulfill the user requirements O To achieve this, we must create both a logical design and physical design O Coding does not occur here!!!

Design Stages: O Choosing an appropriate Database Management System (DBMS) O Establishing system security standards O Interface Design

O Data Capture Requirements O Standards for printed report production O System navigation methods

O What are possible solutions? Buy packaged software - prewritten software available for purchase Write own custom software – software developed at user’s request Vertical market software — designed for particular industry Horizontal market software— meets needs of many companies Outsource – have outside source develop the software

Key Deliverables O Functional Specification Document O data, processes, inputs, outputs, etc. O Technical Specification Document O programs, files, network, etc. O Implementation Schedule

Phase 4: Implementation O We now need to convert our physical system specifications into a working and reliable solution O This is where we develop our system O This is followed by testing and then implementation

Implementation Stages: O Coding O the physical design specifications are turned into working computer code O Integration and Testing O We create a testing environment where all our components are brought together O Installation O The new system is rolled out

Key Deliverables O Fully Installed system O Fully trained users O User and Operational Documentation

Phase 5: Maintenance O Occurs once the system is operational O Monitor system performance, and rectify bugs O Make requested changes

Key Deliverables O Keep system live O Maintain code O Update software when required

Overview of SDLC Establishes a high-level view of the intended project and determines its goals. Analyses end-user information needs in terms of what the IS should do. Describes desired features and operations in detail - how the parts of an information system should be implemented Convert final physical system specifications into working and reliable software Software Changes are made here!

Questions O Q1: What is meant by SDLC? O Q2: What stage of the SDLC are requirements gathered and structured? O Q3: At what stage does coding take place?

Thanks O Any questions?