Case study

Astrid Winterblossom is pleased with your work so far and has asked you to go on to implement your design. However, like so many clients, she wants to make some changes to the requirements. As it turns out, people were not very keen on formalising the swapping part of their activities, although they would still like to view the various skills that other members have and are prepared to help others with. The swaps themselves will probably continue informally, but will NOT be recorded as part of the database at this stage.

However, the event advertising part of Astrid’s garden community has proved to be very popular, and she would like you to develop this part as a priority, with the resultant system renamed GardenFriends. She has a revised set of requirements based on feedback from the community.

Astrid’s revised requirements are as follows:

• As before, all people who host or attend an event must be registered on the GardenFriends database, with the same requirements for registration information as stated previously. This includes a list of the services/skills they are prepared to offer.
• There are three categories of events: Open Gardens, where attendees are taken round a member’s garden where features of particular interest are pointed out; Skills and Techniques, where attendees learn skills such as composting or chainsaw maintenance; and Know Your Plants, which focuses on the cultivation of a particular species or group, such as roses or Banksias.
• Every event has an organiser, as well as an event leader who presents the event on the day (these may or may not be the same person). Some events also include additional helpers who assist in providing 1:1 assistance to attendees. These helpers come from the pool of registered members and each helper may volunteer to assist in many different events.
• The event information required is similar to before (i.e. title, description, date, location, and number of places available), but additional information has also proved useful and is to be included in the final system. In particular, Astrid would like to ensure the postcode of the location is collected, and any instructions to participants included (“bring your own trowel and secateurs” or “don’t forget your hat and sunscreen”. She would also like to record
  whether the event meets accessibility guidelines for people in wheelchairs or with limited mobility.
• Astrid would like to open the events to the general public as well as registered GardenFriends members, in the hope that many will be inspired to join GardenFriends. Guests sign up on the website with their name, suburb, mobile phone number and email.

Part 1: Revised ERD and schema (10 marks)

a) Create and submit the ERD for this database that you are going to use as the basis of your implementation.

b) Include a one or two paragraph explanation as to the changes you have made to the ERD on the basis of your feedback from Assignment 1 and/or as a result of having to support the new functionality and views described in this assignment.

c) Show the relational schema in 3NF that will be the basis of your implemented design. Show your relations using the following convention:
RELATION_NAME (PrimaryKey, Attribute, Attribute, … ForeignKey)

Part 2: Data dictionary (20 marks)

Create a data dictionary for your database. This should include:

a) For each table: a definition of each column (attribute), consisting of the column name, brief description of what it represents, its data type and size, domain (allowable values), any default value, whether it is required, whether unique, and any constraints (primary key, foreign key). You can follow the example in Lab 07. Use the data types available in Oracle.

b) For each of the columns that is a foreign key, give the appropriate referential integrity rules (i.e. the “on delete…. ; on update“ etc actions that should apply when the corresponding primary key is altered). The appropriate action should be included whether or not there is a statement in Oracle to implement it.

c) Any business rules (enterprise constraints) that should apply to the database that haven’t already been covered by cardinality or participation constraints.

Note that your data dictionary must be consistent with your ERD and schema.

Part 3: Implementation (30 marks)

Implement the tables for the GardenFriends database in Oracle SQLPlus on arion.murdoch.edu.au. Note the following:

a) All tables should be created as per your ERD and data dictionary; the marker will check your ERD against your tables. You do NOT need to include the SQL CREATE TABLE statements that you used to create the tables.

b) All entity and referential integrity constraints should be created and appropriately named.

c) All columns (attributes) should be of an appropriate data type/size and be set as required, unique or not as appropriate.

d) All domain constraints should be implemented.

e) All tables should be populated with sample data that will allow the marker to test that your database fulfils the application requirements as specified and supports the transactions and views listed below. Also provide the same sample data in your Word document. If you use a screen dump, it MUST be a size that is readable without zooming.
Note you do NOT need to include the SQL INSERT statements that you used to add the data.

f) SELECT, UPDATE, INSERT and DELETE permissions should be GRANTED on all database objects (particularly tables and views) to the user MARKERTL. This is most important. If you do not grant this permission, the marker will not be able to mark this part of your assignment and you will not get any marks for it.

g) Please state in your documentation whether you have used your V account or H account.

Part 4: Views (40 marks)

Create VIEWS for the following in Oracle (views should be named as ViewA, ViewB etc). Note that some of these have changed from Assignment 1 in line with Astrid’s new requirements.

You should also provide the CREATE VIEW statements you used to create the views in your Word document. These should be as text, not screen dumps.

A. All the members represented in the database, and details of the skills they offer, listed in alphabetical order of last name.

B. A list of all the equipment available for loan, the contact details of the member who is loaning the equipment, and any specific information about the conditions of loan.

C. A list of attendees (name, phone number, and whether they are registered members or guests) who have signed up for Fran Forklift’s workshop on ‘Chainsaw use and maintenance’.

D. All the events (title, date) that were more popular (i.e. higher attendance) with guests than with registered members.

E. All the upcoming events (title, date, location) in a given postcode (e.g. 6150) for the next month (i.e. the whole of the next calendar month).

F. Details (title, description, date, location, leader name, instructions) of all the events that mention roses.

G. Names of any members who have organised, led or helped in more events than they have attended as participants. The result table should also show the number of events.

H. All the events (title, date, leader) that meet accessibility guidelines.

I. A list of guests who attended (or are signed up to attend) events that are not in their home suburb. The result table should also show their home suburb and the event suburb.

J. The number of unfilled places in each category of event that has been held so far.