COMP3311 Notices

Update: In-Person Location for Upcoming Consultation Sessions

Posted by Wenqian Zhang Friday 01 May 2026, 11:23:37 AM.

Hi Class,

I am pleased to let you know that we have successfully secured a physical room for our remaining consultation sessions next week.

If you prefer to ask questions in person, please feel free to drop by Quadrangle G025 during the following times:

• Tuesday, 5 May: 2:00 PM – 4:00 PM

• Thursday, 7 May: 2:00 PM – 4:00 PM

The online Moodle link will still be active if you cannot make it to campus and prefer to join virtually.

Looking forward to seeing you there.

Best regards,

Wenqian

New Serialisability Practice Video Out

Posted by Jerry He Tuesday 28 April 2026, 12:17:33 PM, last modified Tuesday 28 April 2026, 03:32:01 PM.

A new video on serialisability practice questions is now available!

<u><u> https://www.youtube.com/watch?v=nmaxWIY3Ol8 </u>
</u>

Added to the Lectures page under Week 9 Monday → "Serialisability Practice" link.

Good luck with exam prep!

Upcoming Consultation Sessions (April 28 - May 7)

Posted by Wenqian Zhang Monday 27 April 2026, 10:28:05 PM, last modified Tuesday 28 April 2026, 03:31:12 PM.

Hi Class,

I will be holding several consultation sessions over the next two weeks to assist you with any questions regarding the course content, assignments, or marks.

Whether you need clarification on specific concepts or have general inquiries, feel free to drop by during the following times:

Tuesday, 28 April: 2:00 PM – 4:00 PM

Thursday, 30 April: 2:00 PM – 4:00 PM

Tuesday, 5 May: 2:00 PM – 4:00 PM

Thursday, 7 May: 2:00 PM – 4:00 PM

Location Details:

Please note that these sessions will currently be held online only. You can find the link to join on the course Moodle page (click Online Tutorials and Help Sessions). If an offline location becomes available or changes, we will notify you via email.

I look forward to seeing you there and answering your questions.

Best regards,

Wenqian

Assignment 2 Marks Released

Posted by Wenqian Zhang Sunday 26 April 2026, 11:01:33 PM, last modified Tuesday 28 April 2026, 02:23:43 AM.

Hi Class,

The marks for Assignment 2 have been released on Moodle for all students who submitted without an extension. If you were granted an extension, your marks will be updated in approximately one week.

If you have any questions regarding your mark, please contact your marking tutor directly via email by Wednesday, April 29th.

Best regards,

Wenqian

COMP3311 Final Exam — Database Schema

Posted by Wenqian Zhang Friday 24 April 2026, 05:17:53 PM.

Hi all,

A quick note on the database you'll be working with in the 26T1 Final Exam:

The exam database is a lightly modified version of the Assignment 2 database. The core tables and relationships are essentially the same as what you already know from Ass2.

You do not need to learn a new schema. If you were comfortable navigating the Ass2 database, you'll feel right at home during the exam.

Good luck!

Wenqian

COMP3311 Last Lecture & Final Exam Notice

Posted by Jerry He Thursday 23 April 2026, 09:34:04 PM, last modified Thursday 23 April 2026, 09:34:51 PM.

Dear COMP3311 Students,

Today we concluded our last lecture. We discussed what will be covered in the final exam, previewed the exam database, and revealed the types of questions you can expect.

Please remember that we have one more quiz due this Friday.

FINAL EXAM ALLOCATION

The time and location for the COMP3311 final exam are available. Please check your allocation and read all information on that page carefully:

https://cgi.cse.unsw.edu.au/~exam/26T1/seating/register.cgi/allocations/

IDENTIFICATION POLICY

As per the most updated exam rules, you are only allowed to use your student ID card as identification.

"NO STUDENT CARD, NO EXAM!"

Please review the full exam rules here:

https://cgi.cse.unsw.edu.au/~exam/FAQ/exam_rules.html

Good luck with your exam preparation, and thank you for a great term!

COMP3311 Teaching Team

Update on Today’s Lecture & Serializability Video

Posted by Wenqian Zhang Monday 13 April 2026, 02:53:44 PM, last modified Monday 13 April 2026, 04:06:12 PM.

Hi Class,

Since today's session was cut short due to the fire alarm,we will make a video to cover the last bit about Serializability that we missed.

We 'll post another update once the recording is available. Thanks for your patience and stay safe!

Best regards,

Wenqian

​Past Exam Papers Published! 🚀

Posted by Wenqian Zhang Wednesday 08 April 2026, 05:54:38 PM.

Hi everyone,

We have just released a collection of past exam papers to help you get a head start on your revision. You can now find these resources under the "Exams" section.

Best regards,

Wenqian

Assignment 2 Spec Clarification

Posted by Wenqian Zhang Thursday 02 April 2026, 01:53:35 PM.

Hi Class,

The original spec was a bit unclear about the > prompt behaviour — it only mentioned that "lines starting with > are user input" as an example notation, which could be misread as just a documentation convention.

To make this clearer: your shell must echo every input line back to stdout, prefixed with > (a greater-than sign followed by a space), before processing the command. This is now explicitly stated in the spec.

All examples in both the spec page and the examples page have also been updated to show the full echo -e '...' | python3 ass2.py invocation format, so you can see exactly what the expected input and output looks like.

If you have any questions, please post on the course forum.

Best regards,

Wenqian

Assignment 1 Marks Released

Posted by Wenqian Zhang Thursday 02 April 2026, 11:25:34 AM.

Hi Class,

The marks for Assignment 1 have been released, and you can now check your results on Moodle.

Please note that the sample solution will be released tomorrow. If you have any questions regarding your mark, please contact your marking tutor directly via email.

Best regards,

Wenqian

​Assignment 2 Out

Posted by Wenqian Zhang Monday 30 March 2026, 06:26:25 PM, last modified Monday 30 March 2026, 08:49:10 PM.

Assignment 2 is now available on WebCMS:

https://cgi.cse.unsw.edu.au/~cs3311/26T1/assignments/ass2/index.html

The due date is Tuesday 21st April 2026, 8:59pm

3311 Team

Prac 06 Video out

Posted by Jerry He Monday 23 March 2026, 01:37:15 PM, last modified Monday 23 March 2026, 01:37:27 PM.

https://www.youtube.com/watch?v=Q4JtUaRUF2g&list=PLRalM05yyRqUQu81nFdV2JY4sfqa-gkfm&index=1

Prac 04, 05 Videos Out

Posted by Jerry He Monday 16 March 2026, 10:56:50 AM.

Hi all,

Prac 04 and Prac 05 videos are out:

https://www.youtube.com/watch?v=8F-gkSwiYbE&list=PLRalM05yyRqUQu81nFdV2JY4sfqa-gkfm&index=2

https://www.youtube.com/watch?v=VDUheECb_xU&list=PLRalM05yyRqUQu81nFdV2JY4sfqa-gkfm&index=1

Hope these help you.

3311 Team

Some Clarifications from Week 04 Lectures

Posted by Jerry He Friday 13 March 2026, 11:16:41 PM.

Hi everyone,

Please note that Week 4 Monday and Thursday demonstration scripts are located in:

/import/adams/A/cs3311/web/26T1/lectures/week04-monday/sql/

/import/adams/A/cs3311/web/26T1/lectures/week04-thursday/sql/

We got some interesting questions from lectures this week:

1. Why RETURN NEW in an AFTER trigger?

Even though an AFTER INSERT trigger cannot modify the row being inserted (because the operation is already complete), PostgreSQL still requires a RETURN statement.

• In PL/pgSQL, the trigger function must return a record to satisfy the system's requirements.
• Returning NEW is essentially a standard "handshake" to the database to indicate that the trigger has executed successfully without blocking the operation. It is syntax plumbing , not an indication that you are modifying the data being inserted.

2. Dropping overloaded functions

If you have multiple functions named seq() with different signatures (parameters), PostgreSQL treats each as a unique entity.

• Will it drop all of them? No.
• How to drop a specific one: You must specify the signature. If you only type DROP FUNCTION seq();, the database will error because it doesn't know which version you mean.
• To delete a specific version, include the argument types, for example:
  • DROP FUNCTION seq(int);
  • DROP FUNCTION seq(int, int);

3. Why our user defined mycount(*) fail.

Consider the following user defined aggregate:

create or replace function mycount_trans(state integer, val anyelement)

returns integer

as $$

begin

return state + 1;

end;

$$ language plpgsql;

create aggregate mycount(anyelement) (

sfunc = mycount_trans,

stype = integer,

initcond = '0'

);

You will notice that the following code works:

SELECT bar, mycount(bar) FROM sells GROUP BY bar;

However, the following code does not work.

SELECT bar, mycount(*) FROM sells GROUP BY bar;

This is because, the * symbol is a special token that represents "all columns of the table. The built-in count(*) is a hardcoded exception in the database engine that knows how to count rows without needing a specific column. Our user defined aggregate my count did not implement this exception.

Have a good weekend! Let's have more discussions like this in class.

COMP3311 Team

Assignments 1 autotest release

Posted by Wenqian Zhang Friday 13 March 2026, 05:01:34 PM.

The autotest for Assignment 1 has been released. You can use the following command to test your work: 3311 autotest ass1

Week 4 and 5 Help Sessions

Posted by Kenneth Li Monday 09 March 2026, 04:53:18 PM, last modified Friday 13 March 2026, 11:05:00 PM.

Reminder that help sessions for Assignment 1 are available in Weeks 4 and 5, with the first one being tomorrow. Please check the times and locations for these sessions in the "Help Sessions" section on the WebCMS sidebar.

Week 4 Thursday Edit: Help session room change to Mathews 226.

Week 4 Tuesday Edit: To access the Level 3 Matthews rooms, you will have to use the lifts as the stairs won't work. A lift is located around here with the red circle.

​Assignment 1 Forum Question Guidelines

Posted by Kaiyu Chen Monday 09 March 2026, 01:00:22 PM.

• ass1-general : Post clarification questions about the assignment here so everyone can see the answers.
• ass1-private : Post questions that include your code here. These topics are private and only visible to you and the course staff.

​Assignment 1 Out

Posted by Jerry He Friday 06 March 2026, 05:20:41 PM, last modified Saturday 07 March 2026, 12:46:49 PM.

Assignment 1 is now available on WebCMS: https://cgi.cse.unsw.edu.au/~cs3311/26T1/assignments/ass1/index.html

The due date is 9PM Friday Week05. (20 March 2025)

3311 Team

Prac 03 Video Out

Posted by Jerry He Friday 06 March 2026, 04:34:03 PM.

Hi all,

Prac 03 video has been made and relased:

https://www.youtube.com/watch?v=pKa52Qxcwzk

Jerry

Week 3 Monday & Thursday SQL Files

Posted by Jerry He Thursday 05 March 2026, 07:59:10 PM, last modified Thursday 05 March 2026, 08:04:17 PM.

Hi all,

You may use the following command to copy the demonstrated SQL files to your current directory within VXDB02.

Week 3 monday:

cp /import/adams/A/cs3311/web/26T1/lectures/week03-monday/sql/*.sql .

Week 3 Thursday:

cp /import/adams/A/cs3311/web/26T1/lectures/week03-thursday/sql/*.sql .

Best,

Jerry

About Quiz one

Posted by Jerry He Tuesday 03 March 2026, 04:57:09 PM.

Hi everyone,

We are offering another chance to take Quiz 1 for those who missed it. This is a different quiz. We understand students might miss it because they could not have access to course materials in the early stage.

https://webcms3.cse.unsw.edu.au/COMP3311/26T1/activities/quizzes/2464

(If you took old quiz one and still want to take this, no problem. We will take maximum mark of the two.)

For the remaining quizes, please remember to take them. They are due at Friday midnight,

Best,

Jerry

Week 02 lecture Remade

Posted by Jerry He Friday 27 February 2026, 11:51:55 AM.

Hi everyone,

Due to a tech issue, our lecture recording of week 2 thursday is without audio. I have contacted tech support to address this issue ASAP.

For students in online strean, I have made a new video in replacement :

https://www.youtube.com/watch?v=TFBamAUDJJI

The SQL files in the demonstration can be found in: /import/adams/A/cs3311/web/26T1/lectures/week02-thursday/sql/

best,

Jerry

Prac 02 Video Out

Posted by Jerry He Monday 23 February 2026, 06:06:09 PM.

Hi everyone,

I made a video about prac 02:

https://www.youtube.com/watch?v=0T-_85yLIV4&list=PLRalM05yyRqUQu81nFdV2JY4sfqa-gkfm

Best,

Jerry

Week 1 Thursday Recording & Echo360 Activation for Live Lectures

Posted by Jerry He Friday 20 February 2026, 11:53:02 AM, last modified Friday 20 February 2026, 11:55:33 AM.

Hi Everyone,

The recording for the Week 1 Thursday lecture is now available on both Echo360 and Youtube .

Action Required: Activate Echo360 for Week 02 Live Streams

The University Tech team has finalized the setup for our Live Lectures starting next week. To ensure you have access, please "activate" your account by clicking the Echo360 link via one of our official platforms:

• Primary: Webcms
• Alternative: Moodle (under "Lecture Recordings")

You should be able to see a list of 17 arranged lectures, two of which are already completed.

Accessing the platform through these links confirms your UNSW identity and marks you as "Activated" on my end. Please do this before next week to avoid login issues during the live stream.

Have a great weekend!

Best,

Jerry

Prac01 Video Available

Posted by Jerry He Tuesday 17 February 2026, 05:11:35 PM.

Hi everyone,

To better assist you with the vxdb02 environment, I made a video about prac01:

https://www.youtube.com/watch?v=mMsvWMlgoCQ

Best,

Jerry

Welcome to COMP3311 2026 T1

Posted by Jerry He Monday 16 February 2026, 01:51:11 AM.

Hi Everyone,

Welcome to the Term 1 offering of COMP3311 in 2026.

I am Jerry, the lecturer of this term.

Our Course Webpage is avalible in WebCMS3: https://webcms3.cse.unsw.edu.au/COMP3311/26T1/
Here you will find links to all the course material.

Moodle will only be used to access Online Help Sessions (starting week 4) and lecture recordings in Echo360.

Our first lecture is today (Monday) from 1PM to 3PM in Physics Theatre (K14).
https://www.learningenvironments.unsw.edu.au/physical-spaces/k-k14/k-k14-19

The recording will be avalible in Echo afterweards.

From week02 onward lectures will be viewable live in echo360, but this takes time for IT to setup so will not be avalible for the first lecture.

We also have lectures on Thursdays from 2PM to 4PM in Physics Theatre (K14).

Students in the online lecture stream are welcome to attend in-person lectures if there is room in the theatre which there usually is after week 1

COMP3311 runs 1.5 hour Tutorals starting week02 ( NOT THIS WEEK ).
We have a fantasic team of tutors who will be teaching tutorials this term.
We have 4 online tutorials this ter, which will be recorded.

COMP3311 will be using DIscourse as our course forum, infomation on how to access Discourse is avalible on the course website:
https://webcms3.cse.unsw.edu.au/COMP3311/26T1/resources/116933

If you have a personal or private issue, please email the course email alias <cs3311@cse.unsw.edu.au>.

Looking forward to seeing you guys today!

Jerry

COMP3311 Lecturer