Assignment

Objectives-

• To develop a conceptual data model diagram
• To perform logical design

Assignment Specification-

In this assignment, you need to perform the following tasks for the given case study:

• Draw an Entity Relationship (ER) diagram
• Perform logical design
• Create 3NF Relations

Case Study-

The CQ-Council (hereafter called as council) posts a full page advertisement, in local newspapers once a month, displaying all the Development Plan applications (here after called as application) that have been received during the previous month from the developers/ owners of the plots under the council's purview. 

General public members are allowed to raise objections against the applications that appear on those advertisements within a certain period of time, such as two weeks from the date of the advertisement.  The council maintains the details of those objections and the respective application details.  The council maintains all such objections even if they are from an anonymous member of the public. 

The council also maintains detailed records of the following:

• suburban areas in the council
• lots in each suburban area
• subdivision/merger plans
• plots and owners

For your information, the council designates some of its suburban areas for recreation, community, commercial, residential, etc.   Some parts of the land, in each suburban area, are allocated for approach road and street facilities.  The remaining land in a suburban area is further divided into land parcels (here after called as lots). Each of such lots has a unique lot number and details of at least three boundaries and at most four boundaries. 

Generally speaking, only one building is allowed to exist in one lot.  A developer, on behalf of the owner(s) of a lot, or an owner-developer of a lot (both of them are here after called as applicant) can submit an application to the council.  The applications will be received for commercial and residential area only.  Occasionally, the applicants can apply for merger of lots or subdivision of lots to create new land parcels.  The details related to mergers and sub divisions of lots have not been provided here as they are not covered in the proposed information system. 

If the application is complying with the council's developmental policies then the council officers issue a clearance tag to that application.  Rejection letters are issued for the remaining non-compliant applications. Subsequently, they also verify the objections raised by the public on those clearance-tag-applications and discard all the irrelevant objections which are not in line with the council's developmental policy.  If a clearance-tag-application is still left with the objections which are in line with the council's policy then that application is rejected and a rejection letter is issued accordingly.  Thus an application is considered to be a successful application if it has received the clearance tag from the council and does not have any relevant objection from the public.  All the other applications are considered to be unsuccessful applications.  Each successful application will be given a unique clearance number and the date of its clearance is recorded.

The purpose of an application can be for any of the following:

• extension of the existing building
• demolition of existing building and/or construction of a new building
• tree removal
• subdivision of a lot/merger of lots

The council requires that each of the tree removal application must contain the number of trees to be removed from the relevant lot.  Even though the applicable council charges for various purposes may change over a period of time, you can assume that they are fixed charges in the proposed information system.  At the time of lodging an application, the applicant has to pay the total charges of the application to the council.

For each of the successful development applications, the council inspectors may perform many site-inspections such as tree-removal, building foundation, building occupancy, etc., and record their date of visit and approval/non-compliance details if any.  Only one council inspector is involved in each inspection and it is needless to say that only appropriate inspections are conducted for appropriate purposes.  Based on the inspection reports submitted by its inspectors, the council will issue building occupancy certificate and tree removal permission to the respective applicants.

Assignment Requirements

You are expected to create an information system to cater the above information needs of the council.  In this assignment, conceptual and logical design phases of the development of that information system have to be carried out.  The attributes for various entities have not been purposely described in the case study so that the students are encouraged to further research and list the pertinent attributes in addition to the required identifier for each and every entity in their ERD. 

1. Draw an appropriate ER diagram

Use the symbols as prescribed in your course-textbook to draw the ER diagram (ERD) for the above case study. 

Your ERD must

• show all necessary entities, attributes and relationships
• show identifiers/identifying attributes as necessary
• show multi-valued attributes, if any
• show participation and cardinality
• show associative entities, if appropriate
• show weak entities, if any
• use the notation described in the set text
• use consistent and appropriate naming for entities and attributes as specified in the course text book

Some business rules or other aspects of the case study may not be clear to you when you read the case study. If this is the case, then you should either approach your lecturer or tutor for clarification, or you may simply make an assumption and then develop your ERD accordingly. For example, the case study might not mention all relevant participation information (also called minimum cardinalities). If so, you may make an assumption about what the minimum cardinalities might reasonably be, and then show them in your ERD accordingly. You should justify each assumption in terms of the business, for example: it is assumed that each customer must have at least one order because it is assumed that the business does not record customer details until the customer places an order.

To get yourself started, ask yourself, 'If I were running this business, what things I need to keep a list of?'  Write those things down.  For each thing, what information would you need to record about it? How can it be identified? The answers to these questions will help you to develop your ERD.

2. Assumptions and Business rules

Provide assumptions and business rules relevant to your ERD.

3. Create Logical Design:

Map your Entity Relationship diagram (ERD) into relations and make sure that all the relations are in 3NF.  Provide all the relations in the following format:

-Customer (CustomerId, customerName, Street, Suburb, State, PostCode, Email)

-Invoice (InvoiceNumber, invoiceDate, Total, CustomerId) foreign key (CustomerId) references Customer(CustomerId)