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Advanced Diploma in Data and SystemsAnalysis: Assignment Three

Due date: 26 March 2012

Acceptable file types: doc, txt, html, htm, jpg, jpeg, gif, rtf, ppt, xls, zipMaximum number of files: 10If there is more than one file, please combine in a single zip file.

Full instructions for how to submit your assignment are provided in the documentAssignment submission and extension instructions, which you will find on the unithomepage of your course website.

Total marks for this Assignment: 100.

Assignment

This assignment is based on a scenario which has been constructed to provideassessment of a range of topics covered by the unit. There is therefore a degree ofartificiality in the scenario, and in the way in which the information is presented.

You are asked to assume that the data model has been agreed and you are given anentity relationship diagram and the names of the attributes of some of the entities. You

are not, however, given a detailed data model (for example, including domains, datatypes and constraints) because we ask you to make decisions about these things in theassignment.

In order to limit the amount of routine work involved in the assignment some attributesyou might expect to see (for example the address of a person or an organization) havebeen omitted. We do not expect you to identify additional routine attributes of this type.We do, however ask you identify some of the attributes that are required to implementkeys and the required relationships between relations.

The scenario (Wallaces Widgets) on which the assignment is based is provided in theappendix to this document.

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Question 1 [ 25 marks]

This question is based on the Wallaces Widgets scenario and covers the material in

topic 1 of the unit

1(a)Identify the users in the database environment. In each case identify thedata to which they need to have access, and the appropriate level ofaccess (for example read, write, data definition) that they need in order touse the database as intended. (300 words) [7 marks]

1(b)Identify and explain how these levels of access can be implementedthrough:

(i) the database design

(ii) the user interfaces

(300 words) [9 marks]

1(c)Identify any risks to the data, or other misuse that might occur, despiteanything you propose in part (b), and suggest policies or technologies toaddress them. (300 words) [9 marks]

Question 2 [ 25 Marks ]

This question is based on the material in topics 2 and 3

Produce a formal schema for the Wallaces Widgets database, using the methodologyintroduced in topic 3 of the unit, including, where necessary, the relational algebra

introduced in topic 2.

Domains, attributes and keys (13 marks)

Identification and definition of constraints. (12 marks)

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Question 3 [15 Marks]

This question is based on topic 4. It involves producing the SQL expressions that would

be used to implement and query the database designed in question 2. For each part ofthe question include in your answer the SQL expression which would produce therequired result.

(a) The creation of the Booking table [3 marks]

(b) A new entry in the Vehicle table with:

RegNo: W 567 WDD

Make: Ford

Model: Mondeo

MOT: 23/3/2008

contractedServicer: 23 [1 mark]

(c) An amendment to the above inserted record to correct the date

to 23/2/2008 [1 mark]

(d) The number (just the number not a list) of bookings authorised byteam leader Bob Lockhart since 1st January 2006 [4 marks]

(e) Show in a single column the full names of all employees who have booked a vehiclefor which the contracted servicer is the Garage called Fleet Services Ltd.

[3 marks]

(f) The following list (which shows the number of employees in each category)including the headings as shown [3 marks]

Category NumberT 1R 3

O 3

Question 4 [15 marks ]

This question requires knowledge of all the topics but is mainly concerned with issues

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Question 5 [20 marks]This question requires knowledge of all the topics but is mainly concerned with issuescovered in topics 5 and 6. You should, however, draw also on your own experience

and/or research.

Since introducing the new system (discussed in 4 above) Wallaces have made their carpool available to other firms in the area. This started off in a small way, companies withsmaller pools being helped out from time to time, but the practice is growing. Where thishappens there is either a mutual swap arrangement or ad-hoc agreements aboutsharing costs.

Wallaces Widgets are thinking of floating off their car pool operation as a separatecompany. It would be essentially a vehicle hire business, though it would specialise inproviding services to the firms on the trading estate and surrounding area. There seemson the face of it to be a good business case because the replacement of the existingindividual car pools would:

produce savings in the costs of management and administration;

make it possible to manage with a lower aggregate stock of vehicles; enable better deals to be struck for supply and maintenance.

The success of the enterprise is dependent on sufficient firms using the service and so astudy group has been set up of interested parties to report on the broad requirements ofthe proposed system. For some firms, there would be little change, since they could usethe new system directly, in the same way as Wallaces own employees. In a number offirms, however, the car pool usage and cost figures are an essential part of theirintegrated ERP (Enterprise Resource Planning) systems. They need to make bookingsthrough these systems in order to allocate costs and control business processes. Thereis some concern that under the new system users might have to book pool cars throughthe new companys system whilst continuing to record bookings in the existing integratedsystem.

There is no easy answer because these firms use different ERP systems involving a

variety of platforms. The study group has raised this duplication as a serious barrier buthas suggested that the problem be addressed by the new company making its bookingservices available as a Web Service.You have been asked to make a preliminary report on this idea. You are not asked toproduce a formal design, nor even a detailed feasibility study, but they would like you toprovide:

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Appendix 1

Wallaces Widgets Scenario for Unit 3 assignment

This scenario is rather artificial, being designed to test a range of topics whilst keeping toa minimum the routine work involved. Some attributes you might expect to see (forexample the address of a person or an organization) have been omitted. We do notexpect you to identify additional routine attributes of this type.

You are also provided with an entity relationship diagram of the proposed system. Thereare two versions: one is in the Information Engineering style and the other is in the styleused in unit 2 of this course. You do not need to consider both of them. They representthe same model and we advise you to use whichever of them you are most comfortablewith.

Employees of Wallaces Widgets are able to use a pool car (subject to availability)whenever they have a business need for one. Each booking is for one working day.

The existing booking system involves the car pool staff taking telephone or in-personbookings. The records consist of booking forms that are filed in date order and aspreadsheet which records for each day which vehicles have been booked. The bookingforms frequently get out of order or lost and the spreadsheet is often not up to date.There have been instances where an employee has booked two vehicles for the sameday. Some of these instances may have been accidents but there is a suspicion avehicle is sometimes booked for a family member.

Under the proposed system local staff will continue to telephone the booking staff whowill make bookings, but all staff will now be able to access a list of their own bookingsfrom their workstation. Sales and Service Engineers need to be able to make bookingsfrom home or from clients premises, and it is proposed that they should be able to dothis themselves using a browser.

The car pool manager wishes to be able to carry out research into patterns of usage and

respond to ad hoc requests for management support information from seniormanagement. (You can assume any necessary training will be given).

A number of garages are retained to service the vehicles. Each vehicle is allocated to aparticular garage and the car pool staff ensure they are serviced by the contractedgarage at the right time, and that MOT certificates are renewed as required. (For the

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The data to be kept in tables based on these entities should include

Employee

employee number - integers in the range 1000 -5000nametelephone numbercategory - T R or O (team leader, regular user or occasional user)team leader - the employee number of the employees team leader

Vehicleregistration numbermakemodelMOT date - ( the date the Inspection certificate expires or first becomes due).contractedServicer

GarageGarage NumberNamePhone number

Under the new system bookings will need authorisation by a team leader. (There may betimes when employees are not attached to a particular team so the system must allow

any team leader to authorise any booking. A team leader cannot certify his own booking,and needs the authorisation of another team leader. (The authorising team leader neednot be involved in the actual booking process because the information given by theemployee is taken on trust, subject to occasional cross checks by the car pool staff.)

It should not be possible for an employee to book two vehicles for the same day.

It should not be possible to book a service with a garage other than the one contractedfor that vehicle.

It should not be possible to book a vehicle if the MOT expires before or on the bookingdate.

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Appendix 2 - Entity Relationship Model