Requirement Analysis- Weeoaak 2

7/27/2019 Requirement Analysis- Weeoaak 2

1/9

Requirements Analysis

OOA- UWS- Spring 2013


2/9

Object Oriented Analysis- UWS- 20132

Introduction

The client and software developer have to work togetherto get to a situation where each party fully understandswhat is required by the software. We call thisrequirements analysis.

Requirements analysis is important because the client

and developer might have different understanding ofwhat the system has to do. Consider this example: Ageand DOB are the same from the clients point of view (theclient is only interested in verifying that his or hercustomers are adults.) But from the developer point of

view these are different. (with age you only need torecord a number, with a DOB you might need to input theday, month and year.)

Successful software development relies on having a clearand detailed understanding of what is required.


3/9


1. Specifying Software

The Problem Statement

The starting point of any software project is the statementof requirements (Problem statement). It is usually written in a natural language such as English and can

be a few pages in length.

It is written using terms of the clients business rather than incomputing terms.

Its primary purpose is to describe the application area (the real-world context within which the system is required to operate) andwhat the client requires of the system.

Normally, the less experienced in computing a client is,the smaller the statement of requirements will be.

There are two types of information in the problemstatement that need to be identified using requirementsanalysis: Behavioral requirements: What the client wants the system to do.

Constraints: The limitations on the system.


4/9


2. Example

In this section a problem statement is provided bythe client to the analyst (that is us.)

The problem statement is brief, and our aim is to do

a requirements analysis so we can understand

exactly what the system should do.


5/9


3. The Hospital Admission and Treatment

System (The problem statement)

We start by giving you a statement of requirements for part of asoftware system to deal with the treatment of patients in ahospital:

This part of the system is concerned with the admission,treatment and discharge of patients. When a patient is admittedto the hospital, he or she is placed in the care of a team of

doctors. Each team is headed by a consultant doctor who isresponsible for the patients assigned to that team. A record hasto be kept of the doctors in a team who have actually treatedthe patient. The system should be able to: Record the admission of a patient to the hospital;

Give a list of the doctors who have treated a patient;

Give a list of the patients that a team cares for together with theward that each patient is in;

Process the discharge of a patient from the hospital.


6/9

HAT Problem statement

Now the analyst did not understand the requirementsof the system properly and decided to do a

requirement analysis. The analyst has prepared a

set of questions to be asked to the client and called

the client for a meeting. The analyst is hoping thatthis meeting will help him understand what exactly

the client wants the system to do.

So the analyst went to the client and the following

questions were asked:


7/9

7

3. The Hospital Admission and Treatment System(Asking Questions)

Analyst: What information do you need to record about patients when

they are admitted to the hospital? Admin (client): Well, their name and address. Oh, and their age.

Analyst: you want that in number. Admin: No, not their age, their dateof birth.

Analyst:Dont you record whats supposed to be wrong with them?

Admin: No, the consultant looks after that side of things. All we need to

do is to note who the consultant is. Analyst:Im confused what is a consultant ?

Admin: Each patient is under the responsibility of a particularconsultant. We are told which one when the patient is admitted.

Analyst: So how do you identify which consultant it is? Do they havesome kind of identification numbers?

Admin: No. We just use their team code.

Analyst: So you make a note of the consultant responsible for thepatient by recording their team code?

Admin:Thats it.


8/9

8

3. The Hospital Admission and Treatment System(Asking Questions)

Analyst: Does this mean that all the consultants on a team are

responsible for the patient? Admin:No, you dont understand. There is only one consultant on each

team. The consultant is the leader of the team. I thought Ive made thatclear in my problem statement.

Analyst: Well, yes, it did say that each team was headed by aconsultant. I just hadnt realized that there werent any other consultants

on the team. Now then, lets see You say you record the team code.What exactly is a team code?

Admin:Its just a name we use for the team. For example we have an A& E Emergency team, a Pediatrics team, an Orthopedics A team, anOrthopedics B team and so on.

Analyst:Right, I think Ive got that. So lets just check. When a patientis admitted you need to note their name, address and date of birth aswell the code of the team that cares for the patient. Is that all?

Admin: Well, of course, we need to know what ward the patient is on.

Analyst: ok so I will add the ward number

And so on


9/9

Results

After asking these questions. The analystunderstands now what the system should do. Here

are some examples of Information learnt from the

requirements analysis which are not clear in the

problem statement:1. Behavioral requirements (what the system should

do):

The system should record the name, address and

DOB of patients.2. Constraints:

A team can only have one consultant

and so on

Requirement Analysis- Weeoaak 2

Documents

Transcript of Requirement Analysis- Weeoaak 2