Information engineering
Requirements analysis | Information analysis | Data model (stores | normalisation )

Data analysis - Case study

In order to follow an Information Engineering approach to system design we will use a small case study;

This club is made up of members, and a small elected executive (President, secretary, and board members), a librarian is also appointed.
The system is required to keep track of invoices and payments (for subscriptions).
Further, the club operates a small library.
Here, the system is required to keep track of who has taken out the books, and when they were taken out and when returned.
A historical record is required so that an analysis of the use of each book can be established.

Requirements analysis

A small service club that currently has about 50 members has approached you. It is in an expansion phase and numbers are expected to grow rapidly.

Two basic requirements have been identified.

The ability to manage membership data, including tracking of subscription status (amounts owing)
The ability to manage their library of books.

Terms of reference

You are to analyse the situation, and produce an analysis of data flows, a data dictionary and Entity relationships.
You are not to design the individual program processes.

Resources

Hardware
The club have just been donated a single stand alone Personal Computer, with a Laser Printer.

Membership
The secretary will maintain the database of members, and is already computer literate.

Library
The library consists of approximately 500 books, though this number is increasing. All books are kept in one location.

Constraints

Hardware
Single computer, with a laser printer

Users
Two people will have access, the secretary and the librarian.

Membership
A complete transaction record is required of invoices and payments.

Library
All books are stored in a cabinet on one site.
No reservation system is required. If a book is on the shelf it may be taken out.

Objectives and Scope

To maintain up-to-date records of members and maintain an efficient library book borrowing system.

Benefits

Complete and current membership lists
Easily produced membership list
Easily produced member status reports
Accurate tracking of books owned by club
Data is easily backed up

Costing

These should include estimates for;

Data analysis
Possible software costs
(Note: at this stage you should not be recommending a software product.)
Installation costs
Training costs.

Recommendations

Having investigated all aspects of this projected project I would recommend that the project proceed to the Analysis stage.
Note: at this stage you should not be recommending a software product.

Information analysis - Data flow diagrams

Context diagram.

A common way to begin is to model the whole system by one process, and show the external entities and the data flows between these external entities and the system. [ITH]

Level 1 DFD

We now introduce the components of the system and some of the data stores.

Level 2.1 DFD

Level 2.2 DFD

Level 3 DFD

Data modelling

Data stores

Member file

Member Code
Member Name
Member Address 1
Member Address 2
Member Address 3
Member Phone
Member Spouse Name
Member Child Name (0 .. n)
Member Child Birthdate (0..n)

Transaction file

Transaction Date
Transaction Number (auto increment)
Transaction Type (I=Invoice, P=Payment)
Transaction Amount

Book file

Book ISBN
Book Title
Book Author
Book Internal Id
Book Purchase Price
Book Borrowed Date
Book Returned Date

Normalised files

Here we will end up with 6 files;

Member Masterfile Data

Member Code
Member Name
Member Spouse Name
Member Address 1
Member Address 2
Member Address 3
Member Phone

Member's Children

Member Code
Member Child Number
Member Child Name
Member Child Birthdate (optional)

Member Transaction Data
(Payments/Invoices)

Transaction Date
Transaction Number (auto increment)
Member Code
Transaction Type (I=Invoice, P=Payment)
Transaction Amount

Library Book Masterfile

Book ISBN
Book Title
Book Author

Library Book Internal Unique Id Code

Book Internal Id
Book ISBN
Book Purchase Price

Library Book transaction file

Transaction Date
Transaction Number (auto increment)
Book Internal Id
Member Code
Transaction Type (B=Borrowed, R=Reserved, X= Cancelled)
Book Borrowed Date (if Reserved type)
Book Returned Date