Project 1 SQL
COMP9311 22T1
The deadline for project 1 is: April 1st 16:59:59 (Sydney Local Time)
1. Aims
This project aims to give you practice in
• Reading and understanding a moderately large relational schema (MyMyUNSW).
• Implementing SQL queries and views to satisfy requests for information.
• The goal is to build some useful data access operations on the MyMyUNSW database. The
data may contain some data inconsistencies; however, they won’t affect your answers to the
project.
2. How to do this project:
• Read this specification carefully and completely
• Familiarize yourself with the database schema (description, SQL schema, summary)
• Make a private directory for this project, and put a copy of the proj1.sql template there
• You must use the create statements in proj1.sql when defining your solutions
• Look at the expected outputs in the expected_qX tables loaded as part of the check.sql file
• Solve each of the problems below, and put your completed solutions into proj1.sql
• Check that your solution is correct by verifying against the example outputs and by using
the check_qX() functions
• Test that your proj1.sql file will load without error into a database containing just the original
MyMyUNSW data
• Double-check that your proj1.sql file loads in a single pass into a database containing just the
original MyMyUNSW data
• Submit the project via moodle
• PLpgSQL functions are not allowed to use in this project
• For each question, you must output result within 120 seconds on Grieg server.
3. Introduction
All Universities require a significant information infrastructure in order to manage their affairs. This
typically involves a large commercial DBMS installation. UNSW's student information system sits
behind the MyUNSW web site. MyUNSW provides an interface to a PeopleSoft enterprise
management system with an underlying Oracle database. This back-end system (Peoplesoft/Oracle)
is often called NSS.
UNSW has spent a considerable amount of money ($80M+) on the MyUNSW/NSS system, and it
handles much of the educational administration plausibly well. Most people gripe about the quality of
the MyUNSW interface, but the system does allow you to carry out most basic enrolment tasks online.

Despite its successes, MyUNSW/NSS still has several deficiencies, including:
• no waiting lists for course or class enrolment
• no representation for degree program structures
• poor integration with the UNSW Online Handbook
The first point is inconvenient, since it means that enrolment into a full course or class becomes a
sequence of trial-and-error attempts, hoping that somebody has dropped out just before you attempt
to enroll and that no-one else has grabbed the available spot.
The second point prevents MyUNSW/NSS from being used for three important operations that would
be extremely helpful to students in managing their enrolment:
• finding out how far they have progressed through their degree program, and what remains to
be completed
• checking what are their enrolment options for next semester (e.g., get a list of available
courses)
• determining when they have completed all the requirements of their degree program and are
eligible to graduate
NSS contains data about student, courses, classes, pre-requisites, quotas, etc. but does not contain
any representation of UNSW's degree program structures. Without such information in the NSS
database, it is not possible to do any of the above three. So, in 2007 the COMP9311 class devised a
data model that could represent program requirements and rules for UNSW degrees. This was built
on top of an existing schema that represented all the core NSS data (students, staff, courses, classes,
etc.). The enhanced data model was named the MyMyUNSW schema.
The MyMyUNSW database includes information that encompasses the functionality of NSS, the UNSW
Online Handbook, and the CATS (room allocation) database. The MyMyUNSW data model, schema
and database are described in a separate document.
4. Setting Up
To install the MyMyUNSW database under your Grieg server, simply run the following two commands:
$ createdb proj1
$ psql proj1 -f /home/cs9311/web/22T1/proj/proj1/mymyunsw.dump
If you've already set up PLpgSQL in your template1 database, you will get one error message as the
database starts to load:
psql:mymyunsw.dump:NN: ERROR: language "plpgsql" already exist.
You can ignore the above error message, but all other occurrences of ERROR during the load needs to
be investigated.


If everything proceeds correctly, the load output should look something like:
SET
SET
SET
SET
SET
psql:mymyunsw.dump:NN: ERROR: language "plpgsql" already exists
... if PLpgSQL is not already defined,
... the above ERROR will be replaced by CREATE LANGUAGE
SET
SET
SET
CREATE TABLE
CREATE TABLE
... a whole bunch of these
CREATE TABLE
ALTER TABLE
ALTER TABLE
... a whole bunch of these
ALTER TABLE

Apart from possible messages relating to plpgsql, you should get no error messages.
The database loading should take less than 60 seconds on Grieg, assuming that Grieg is not under
heavy load. (If you leave your project until the last minute, loading the database on Grieg will be
considerably slower, thus delaying your work even more. The solution: at least load the database Right
Now, even if you don't start using it for a while.) (Note that the mymyunsw.dump file is 50MB in size;
copying it under your home directory or your /srvr directory is not a good idea).
If you have other large databases under your PostgreSQL server on Grieg or if you have large files
under your /srvr/YOU/ directory, it is possible that you will exhaust your Grieg disk quota. Regardless,
it is certain that you will not be able to store two copies of the MyMyUNSW database under your Grieg
server. The solution: remove any existing databases before loading your MyMyUNSW database.
Summary on Getting Started
To set up your database for this project, run the following commands in the order supplied:

$ createdb proj1
$ psql proj1 -f /home/cs9311/web/22T1/proj/proj1/mymyunsw.dump
$ psql proj1
... run some checks to make sure the database is ok
$ mkdir Project1Directory
... make a working directory for Project 1
$ cp /home/cs9311/web/22T1/proj/proj1/proj1.sql Project1Directory

The only error messages produced by these commands should be those noted above. If you omit any
of the steps, then things will not work as planned.
5. Important Advice Before You Start
The database instance you are given is not a small one. The first thing you should do is get a feeling
for what data is there in the database. This will help you understand the schema better and will make
the tasks easier to understand. Tip: study the schema of each table to see how tables are related and
try write some queries to explore/ understand what each table is storing.
$ psql proj1
proj1=# \d
... study the schema ...
proj1=# select * from Students;
... look at the data in the Students table ...
proj1=# select p.unswid,p.name from People p join Students s on (p.id=s.id);
... look at the names and UNSW ids of all students ...
proj1=# select p.unswid,p.name,s.phone from People p join Staff s on (p.id=s.id);
... look at the names, staff ids, and phone #s of all staff ...
proj1=# select count(*) from Course_Enrolments;
... get an idea of the number of records each table has...
proj1=# select * from dbpop();
... how many records in all tables ...
proj1=# ... etc. etc. etc.
proj1=# \q

Read these before you start on the exercises:
• The marks reflect the relative difficulty/length of each question.
• Work on the project on the supplied proj1.sql template file.
• Make sure that your queries work on any instance of the MyMyUNSW schema;
don't customize them to work just on this database; we may test them on a different database
instance.
• Do not assume that any query will return just a single result; even if it phrased as "most" or
"biggest", there may be two or more equally "big" instances in the database.
• When queries ask for people's names, use the Person.name field; it's there precisely to
produce displayable names.
• When queries ask for student ID, use the People.unswid field; the People.id field is an internal
numeric key and of no interest to anyone outside the database.
• Unless specifically mentioned in the exercise, the order of tuples in the result does not matter;
it can always be adjusted using order by. In fact, our check.sql will order your results
automatically for comparison.
• The precise formatting of fields within a result tuple does matter, e.g., if you convert a number
to a string using to_char it may no longer match a numeric field containing the same value,
even though the two fields may look similar.
• We advise developing queries in stages; make sure that any sub-queries or sub-joins that
you're using works correctly before using them in the query for the final view/function
• You may define as many additional views as you need, provided that (a) the definitions
in proj1.sql are preserved, (b) you follow the requirements in each question on what you are
allowed to define.
• If you meet with error saying something like “cannot change name of view column”, you can
drop the view you just created by using command “drop view VIEWNAME cascade;” then
create your new view again.
Each question is presented with a brief description of what's required. If you want the full details of
the expected output, look at the expected_qX tables supplied in the checking script (check.sql) once
we release it.
6. Tasks
To facilitate the semi-auto marking, please pack all your SQL solutions into view as defined in each
problem (see details from the solution template we provided).

Question 1 (2 marks)
Define a SQL view Q1(subject_name):
Give the names of subjects that mentions at least two COMP courses in its prerequisite description,
where one of COMP course mentioned must be a level 3 course (i.e., with a course code of the
format COMP3***).
• subject_name should be taken from Subjects.name field;

Question 2 (3 marks)
Define an SQL view Q2(course_id) that gives the id of the course that holds Studio in at least
3 different buildings.
• course_id should be taken from Courses.id field;

Question 3 (3 marks)
Define a SQL view Q3(course_id, use_rate):
Give the courses that used the Central Lecture Block the most in 2008.
• course_id should be taken from Courses.id field;
• Return use_rate as integer;
• For each course, the value use_rate is number of its classes using a room in Central Lecture
Block building (refers to buildings.name).

Question 4 (3 marks)
Define a SQL view Q4(facility):
Give a complete list of the facilities that do not exist on any of the buildings on UNSW Kensington
Campus with a grid reference that begins with the letter ‘C’.
• facility should be taken from Facilities.description field.
• Each building on the Kensington campus has a grid reference number to denote its relative position on
the map (e.g., CSE building has a grid reference of K17 beginning with the letter ‘K’). This information
exists in the column Buildings.gridref.

Question 5 (4 marks)
Define a SQL view Q5(unsw_id, student_name):
Give the UNSW id and name of all the distinct domestic students who has only ever scored HD in
their courses (refers to the course_enrolments.grade).
• unsw_id should be taken from People.unswid field;
• student_name should be taken from People.name field.

Question 6 (4 marks)
Define a SQL view Q6(subject_name, non_null_mark_count, null_mark_count):
Give the subject name of the course, the number of student marks that are not null, and the number
of students marks that are null. We only consider courses offered in Semester 1 2006 that recorded
more than 10 students with null marks.
• subject_name should be taken from Subjects.name field;
• Return non_null_mark_count and null_mark_count as integer.

Question 7 (4 marks)
Define a SQL view Q7(school_name, stream_count):
Give the schools that have offer more streams than the School of Computer Science and
Engineering. Only consider the streams that are directly offered by an organization unit that is a
school.
• school_name should be taken from Orgunits.longname field;
• Return stream_count as integer.

Question 8 (4 marks)
The university is trying to pair students together for a special project.
Define a SQL view Q8(student_name_local,student_name_intl):
Give all possible combinations of student pairings. The students concerned are all from in course
2012 Semester 1, Engineering Design who scored higher than 98 marks. To encourage some
semblance of international exchange, we want the pair to consist of one domestic student and one
international student, and they both should have the same WAM. (We want each pair to be
formatted as such , exactly)
• student_name_local and student_name_intl should be taken from People.name field;
• Engineering Design refers to Subjects.name.

Question 9 (4 marks)
Define a SQL view Q9(ranking, course_id, subject_name,
student_diversity_score):
Give the ranking, course id, the corresponding subject name, and score of the courses with the
highest diversity scores. We consider a student diversity metric; the value of which is determined by
the number of known distinct countries of origins of all its student members (To help with
comparisons, the university always assumes that there is at least one student with the origin country
‘Australia'). We also only consider scores with a Rank of 6 or above.
• course_id should be taken from Courses.id field;
• subject_name should be taken from Subjects.name field;
• Return student_diversity_score as integer.
• There may be courses with the same diversity score, your result should assign the same rank to courses
with the same score. The Rank() function in PostgreSQL will be able to do this for you for the ranking
column.

Question 10 (4 marks)
Define a SQL view Q10(subject_code, avg_mark):
Give the subject codes (of the related courses) and average mark of all PG-career courses offered by
School of Computer Science and Engineering in Semester 1 2010.
• subject_code should be taken from Subjects.code field;
• Assume that if a student does not have a mark, they have a 0 mark instead.
• Only consider the courses having more than 10 students.
• Use AVG() function when calculating the average marks, save the results as numeric(4,2)

Question 11 (5 marks)
Give the subjects in 2008, where the average mark received by its students increased the most from
semester 1 to semester 2. Define a SQL view Q11(subject_code, inc_rate): Give the
subject code and the increase rate of its average mark.
• subject_code should be taken from Subjects.code field;
• Only consider the subjects offered by School of Chemistry or School of Accounting.
• Only consider non-null marks.
• Increase rate in average mark = (avg_mark of S2 - avg_mark of S1) ÷ avg_mark of S1.
• Round the increase rate to the nearest 0.0001. (e.g., if inc_rate = 0.01, then return 0.0100; if inc_rate =
0.01234, then return 0.0123; if inc_rate = 0.02345, then return 0.0235) This rounding behavior is different
from the IEEE 754 specification for floating point rounding which PostgreSQL uses for float/real/double
precision types. PostgreSQL only performs this type of rounding for numeric and decimal types.

Question 12 (5 marks)
We want to find the total lab class time per week of COMP courses taught by the lecturer(s) who has
a title of Dr. Define a view Q12 (name, subject_code, year, term,
lab_time_per_week): Gives lecturer’s name, the subject code of the course, the year and term
of the course provided, and the total lab class time (hours) per week of the course. Note:
• name should be taken from People.name field;
• subject_code should be taken from Subjects.code field;
• year and term should be taken from Semesters.year and Semesters.term fields,
respectively;
• Return lab_time_per_week as integer; lab_time_per_week is the sum of all lab class time
per week for a course;
• A lecturer refers to his/her Staff_roles.name contains “Lecturer”;
• A lab class refers to its Class_types.unswid is LAB.


Question 13 (5 marks)
Define a view Q13(subject_code, year, term, fail_rate) that gives the fail rate for
the semester with the largest number of enrolled students for each COMP course, only considering
courses with more than 150 students enrolled. Note:
• subject_code should be taken from Subjects.code field.
• year should be taken from Semesters.year field.
• term should be taken from Semesters.term field.
• fail rate = number of students with mark less than 50 ÷ number of students with mark
• When counting the number of enrolled students, consider those with null mark; But when calculating
fail rate, do not consider null mark records.
• Round fail_rate to the nearest 0.0001. (e.g., if fail_rate = 0.01, then return 0.0100; if fail_rate =
0.01234, then return 0.0123; if fail_rate = 0.02345, then return 0.0235).
• COMP course refers to the course whose subject code starts with “COMP”

To explain, the following table gives the information of each PHYS course whose number of enrolled students
is more than 150. The red lines represent the semester with the largest number of enrolled students for each
PHYS course (also # of students > 150).

code | year |term| stu_count
---------------+---------+------+-------------
PHYS1121 | 2010 | S2 | 167
PHYS1231 | 2012 | S2 | 169
PHYS1231 | 2010 | S2 | 183
PHYS1121 | 2012 | S2 | 186
PHYS1231 | 2011 | S2 | 188
PHYS1160 | 2012 | S2 | 196
PHYS1131 | 2009 | S1 | 201
PHYS1160 | 2012 | S1 | 213
PHYS1160 | 2011 | S2 | 217
PHYS1121 | 2011 | S2 | 238
PHYS1121 | 2008 | S1 | 239
PHYS1131 | 2012 | S1 | 258
PHYS1131 | 2010 | S1 | 318
PHYS1131 | 2011 | S1 | 344
PHYS1121 | 2009 | S1 | 380
PHYS1121 | 2010 | S1 | 453
PHYS1121 | 2012 | S1 | 474
PHYS1121 | 2011 | S1 | 524



7. Submission
You can submit this project by doing the following:
• Students must submit an electronic copy of their answers to the above questions to the
course website in Moodle.
• The file name should be proj1_studentID.sql (e.g., proj1_z5100000.sql).
• If you submit your project more than once, the last submission will replace the previous one
• In case that the system is not working properly, you must take the following actions:
• Please keep a copy of your submitted file on the CSE server. If you are not sure how, please
have a look at taggi.
The proj1.sql file should contain answers to all the exercises for this project. It should be completely
self-contained and able to load in a single pass, so that it can be auto-tested as follows:
• A fresh copy of the MyMyUNSW database will be created (using the schema
from mymyunsw.dump)
• The data in this database may be different from the database that you're using for testing
• A new check.sql file may be loaded (with expected results appropriate for the database)
• The contents of your proj1.sql file will be loaded
• Each checking function will be executed, and the results recorded
8. Check your Answers
Before you submit your solution, you should check that it loads correctly for testing by using
something like the following operations:
$ dropdb proj1 ... remove any existing DB
$ createdb proj1 ... create an empty database
$ psql proj1 -f /home/cs9311/web/22T1/proj/proj1/mymyunsw.dump ... load the
MyMyUNSW schema and data
$ psql proj1 -f /home/cs9311/web/22T1/proj/proj1/check.sql ... load the checking code
$ psql proj1 -f proj1.sql ... load your solution
$ psql proj1
proj1=# select check_q1(); … check your solution to question1
…
proj1=# select check_q6(); … check your solution to question6
…
proj1=# select check_q12(); … check your solution to question12
proj1=# select check_all(); … check all your solutions

Notes:
1. You must ensure that your proj1.sql file will load and runs correctly (i.e., it has no syntax errors,
and it contains all your view definitions in the correct order).
a. If your database contains any views that are not available in a file somewhere, you should
put them into a file before you drop the database.
b. If we need to manually fix problems with your proj1.sql file in order to test it (e.g., change
the order of some definitions), you will be fined via half of the mark penalty for each
problem.
c. If your code loads with errors, fix it and repeat the above until it does not.

2. In addition, write queries that are reasonably efficient.
a. For each question, you must output result within 120 seconds on Grieg server. This time
restriction applies to the execution of the ‘select * from check_Qn()’ calls.
b. For each question, you will be fined via half of the mark penalty if your solution cannot
output results within 120 seconds.

9. Late Submission Penalty
20% reduction (-10 out of 50) for each 24 hours after the deadline date and time.