Ana səhifə

LotaCar is a small family car trading business run by Mr and Mrs Lota


Yüklə 20.28 Kb.
tarix25.06.2016
ölçüsü20.28 Kb.


LotaCar
LotaCar is a small family car trading business run by Mr and Mrs Lota.
Every morning Mr or Mrs Lota open the shop and check the mail. If there are any bills to pay they arrange for their payment. They then tidy up the shop, put the kettle on and wait for the first customer.
Customers either phone-in or walk into the shop. Sometimes they want a specific vehicle and sometimes they are not sure what they want and need some guidance. Mr and Mrs Lota provide the necessary guidance and ultimately sell cars.
In order to be able to run their business properly, Mr and Mrs Lota have devised a paper-based system that helps them access details about different car makes. With the continuous addition of new car models this system is becoming cumbersome. Mr and Mrs Lota think that a computerised information system will help them handle the problems inherent in any expanding business such as theirs.
The main aim of Mr and Mrs Lota’s system is to contain information about as many models of as many car manufacturers as they can, since LotaCar does is not tied down to one manufacturer. To keep this system up to date, Mr Lota peruses the trade magazines and adds new models to his system as they are announced. Sometimes, announcements come through the post. Occasionally a new car manufacturer appears on the scene, as Daewoo did recently in the British market, and has to be added to the system.
The addition of a new model to the system invariably leads to a request of model specifications from the manufacturer. These tend to be sent through the post. When they arrive they are promptly added to the system.
Model specifications consist of standard characteristics such as car weight, car length, maximum speed, horsepower, capacity, acceleration, miles per gallon, manufacturer’s unit price, manufacturer’s recommended selling price etc. Also, each model has a set of accessories, such as air-condition, sunroof, electric windows, alarm system, air bags etc. which may come as standard.
The handling of a model’s accessories is a considerable hustle for Mr and Mrs Lota. As new such accessories are announced they have to be added to the system.
When a car is sold a customer record is created to register the customer.

As part of the analysis process a meeting was arranged with Mr and Mrs Lota and their daughter Carlota who is currently in the second year of a Business IT university course. Following some initial observations a Business Activity Model had been produced. This was presented to the Lota family. The main purpose of the workshop was to draw the system’s boundary and to produce a list of requirements.


It soon became clear that the system’s main objective was to hold vehicle information as well as a record of customer sales. The system would not concern itself with financial matters such as producing invoices and tracking bills. It would only concern itself with adding new manufacturers and their models, new model specifications and keeping a record of customers and the vehicles they have bought.
To be useful it was agreed that the system should be able to answer the following queries:
What are the features and accessories of a particular model?

What models have been released by a manufacturer?

What sales have been done in a specified time period?

What vehicles has a customer bought?

What models have a given capacity?

Further data-focused analysis revealed the following:


Each manufacturer registers many model names. For example, Escort and Modeo are registered names of Ford while 205 and 405 are registered names of Peugeot.
Each manufacturer produces many models under each model name. Each model is recognised by its name, its capacity and its designation. For example Citroen’s ZANTIA 1.8 SX or Vauxhall’s CAVALIER 2.0 SRi or Ford’s ESCORT 1.4 GHIA or Seat’s TOLEDO 1.8 DIESEL or Ford’s ESCORT 1.4 LX.
For simplicity each model is recognised by a unique, system generated, model id. Thus each model belongs to one manufacturer’s model name, one capacity and one designation. Clearly many models can share a capacity, such as 1.8 above. Similarly, many models can share a designation.
Customers, over time, buy many vehicles. Each vehicle is of a particular model. Each customer is allocated a unique customer id while each vehicle is recognised by its actual registration number.
For each customer and each manufacturer we hold their name, address and telephone number. For each vehicle bought by a customer we hold the sale date and the sale price.
Each model has many accessories as standard. When a new model is entered it is linked to all the accessories in the system. The link between a model and an accessory states whether the accessory is standard or not for this model. If an accessory is not standard for the model, the accessory’s price for this model is recorded.

One of the requirements of the LotaCar Model Details and Customer Records System stipulates the production of a report showing a model’s features such as the one shown below:




Model Id 004

Model Name Escort

Model Capacity 1.4

Model Designation LX

Accessory Id Accessory Name Standard? Price


001 air-condition N 300.00

002 electromagnetic locks N 250.00

003 air bag Y






The following systems analysis products were produced:




  1. An initial Business Activity Model

  2. A list of requirements

  3. A Data Flow Diagram showing the major update processes

  4. A Data Store/Entity cross reference

  5. A Logical Data Structure

These are appended onto this senario:



1. Business Activity Model - LotaCar





2. Requirements Catalogue Summary - LotaCar




  1. Add new model

  2. Add new manufacturer

  3. Add new customer (add new vehicle)

  4. Add accessory

  5. Add model features and accessories (specification)

  6. Record sale

  7. Show a model’s features

  8. Show a manufacturer’s models

  9. Produce a sales report

  10. Show a customer’s buys (history)

  11. Show all models of a given capacity



3. Data Flow Diagram - LotaCar





4. Data Store/Entity Cross Reference - LotaCar




Data Store

Entities

D1 Manufacturers

Manufacturer

D2 Models

Model Name

Model


Capacity

Designation



D3 Accessories

Accessory

Model Accessory



D4 Customers

Customer

Vehicle




5. Logical Data Structure - LotaCar







Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur ©atelim.com 2016
rəhbərliyinə müraciət