The final exam proved pretty challenging:
Props to Laur, who got a +99XP, and to Gabe, the only perfect +100XP!
Incidentally, the hardest question by far was: “a table with three attributes A, B, and C has one FD: {C}→{A}. What is the key, and is this normalized?” The correct answer is: “the key is {C,B}, and no it’s not normalized.” Only four out of 45 got this right! :-O
To see what your friends (and enemies?) wrote about you and your Demo project, log on to the Redis server on cpsc and select instance #49. Then look for the key that starts with “feedback:” and has your first name. This is a list, and so the lrange command applies.
All in one go:
cpsc$ redis-cli 127.0.0.1:6379> auth SuperSecretClassPassword OK 127.0.0.1:6379> select 49 OK 127.0.0.1:6379[49]> keys feedback:* 1) "feedback:ethan" 2) "feedback:dimitrie" 3) "feedback:caleb-with-a-c" . . and many others . . 127.0.0.1:6379[49]> lrange feedback:yourName 0 -1 1) "Your site totally sucked!" 2) "What a shameless rip-off of Wikipedia!" 3) "Consider Art History as a major!" . . more feedback . .
As you can see, there’s nothing stopping you from viewing (or even editing) other students’ feedback as well. This is another place that the “don’t be a jerk” rule comes into play.
Strong? Studly? Hungry? In the first section of the class? Well, then, this is the opportunity for you!
I need to drop by Giant tomorrow to buy ice cream and such before the first final exam period. I need a friend to help me carry stuff. Ideally two friends, actually, since I’ll need two strong backs (mine doesn’t count) to carry the cooler up the Farmer parking lot stairs and wheel it into the room.
To be eligible for this event (at which you will have some influence over which ice cream flavors get chosen) you must email me immediately with subject line “I’ll do it, Stephen!” I will then pick you up at the bottom of the Farmer basement stairs at exactly 11:30am tomorrow.
Important: you may not touch your own website after 11am on Thursday, period. This is true even during the “other section’s” demo day, and even more especially true during your own section’s Demos. Trying to stealthily work on your own last-minute bugs while your teammates are presenting their work is a sure-fire way to lose major points the moment I catch you.
Okay, to actually register your final project for Demo Day®, send me an email with subject line CPSC/DATA 350 Demo-Day turnin before midnight tonight, and with these items in the body:
Get excited! 
I’m in the middle of these this weekend. Just a note: if you feel you did something above-and-beyond, and it was not noticed or rewarded with extra credit, please do write back and tell me what you did that was above-and-beyond so I can judge and possibly rectify.
For some additional practice before quiz #8 and/or the final, here are some practice Cypher query challenges, and sample solutions.
Quiz #8 (and last) has been posted to Canvas, and is due Sunday at midnight. Good luck!
If you’re curious as to the result, today’s vote counts were as follows:
(This jibes with my own perspective.)
If you feel that you will be unprepared for Thursday the 24’ths final exam because today’s announcement was so sudden — and you had set aside time to study for it after this week is over — I will allow students (on a case by case basis) to take the final exam instead during the “opposite” final exam period from their own. (The two final exam periods are noon-2:30pm and 3:30-6pm on Thursday May 1st.)
Important: if you want to do this, you need to make your case to me in person, no later than end of class tomorrow (Wednesday). If I do not hear from you by the end of class tomorrow, and if I have not approved this exception, you will need to take the final on Thursday April 24th with everyone else, as announced today.
As mentioned in class today, the final exam this semester will be in-person on Thursday, April 24th during regular class time.
It is an open-notes, open-anything-printed-out, open-calculator, closed-computer, closed-other-humans, closed-electronic-devices (other than a calculator), closed-Python, and timed (at 1 hour 15 minutes).
All materials that you use for this exam must be printed out on paper beforehand. During the exam, you are permitted only to work with pencil and paper. You may not use your computer at all for the exam.
Feel free to browse the class website and print out any of the cheat sheets or other materials. Feel free to print out any of the code examples I posted this year. Feel free to print out your own code from any of your homeworks. Feel free to print out all of Wikipedia, if you have the paper and ink. But it must all be printed out and accessed that way during the exam, not using your computer or the Internet.
I think I may have finally licked this thing. See you guys tomorrow.
Blech. See you guys Tuesday (I hope).
Quiz #7 has been posted to Canvas, and is due this coming Monday at midnight. You can go ahead and take the quiz now if you’d like — it doesn’t contain anything we haven’t already covered in class.
“No more training do you require. Already know you, that which you need.” — Yoda
Also, the assignment #8 deadline has been postponed until Friday at midnight.
Okay, so I feel like it’s unfair of me to expect you guys to incorporate Neo4j into your project databases by the end of the semester, considering we’ve missed so much class and I haven’t even taught you guys how to query in it yet, lol. So here’s what we’re going to do for “assignment #9“:
Assignment #9 will be your final presentation (on demo day, a.k.a. the final exam period, a.k.a. May 1st). As I’ll explain more fully in class, you’re going to have two minutes to coherently and compellingly demonstrate your website’s functionality, in all its glory, followed by Three Minutes of Chaos® during which everyone in the class will be accessing your website all at once and adding (clean, tasteful) data to it.
Here’s what I’ll be looking for:
Send questions!
Here are my answers to part 1 of yesterday’s extra credit activities. For part 2, I created a checker script on the cpsc server that lives at:
/home/faculty/stephen/mongoActivity2check.py
You should have read permissions to view this file in vim, run it yourself, etc., to see what you may have missed.
Sorry guys, I’m just not feeling any better. I’m going to try and go to the urgent care today. In the meantime, class and office hours are canceled.
If you attended the department programming contest on Friday, and would like your points, please send me email and tell me how many problems your team solved!
You may have noticed on the cheat sheet that if you’re importing a JSON file that contains a list of documents (rather than a single document) you have to give an additional argument to the end of the mongoimport command:
--jsonArray
I apparently left this off the instructions for part 2 of today’s activity, but you will need it to import starwars.json.
Office hours will regrettably be canceled for Tuesday, April 15th.
If not everybody reads this in time, that’s okay, but I’d like over half the students to have a working laptop during lecture tomorrow (Tuesday, April 15).
Here’s the activity from today’s class (the answer was “happee e-star“) and also another one from last semester to help you practice (the answer is at the bottom of this post).
happea terkey day
The single best computer science book ever written, in my opinion, and mandatory reading for everyone in the discipline at some point in their career.
True story: when I finished the last page on my first read-through, I literally cried. ;_;
So, it seems that Stephen’s git skills are not as sharp as he thought, because I have managed to thoroughly screw up and lose the early class’s Flask code. 🙁 The good news is that we had the exact same agenda in both sections, and added the same features. (The code will vary, of course, as two programs that do the same basic thing always vary.)
All I can say is I’m sorry! And offer a free XP for your pain and suffering.
Here’s the code from yesterday and today:
Hot on the heels of your Redis expansion will be your MongoDB expansion.
It’s due next week! So why are you still reading this?!
Quiz #6 has been posted, and is due Friday at midnight. You can take it any time (including right now) — we’ve already covered all the material on it.
Here are the more complex aggregation pipeline examples from today’s class.
Just because Garrett wanted to.
Here’s the Kahoot from yesterday’s class, if you’d like to practice with it.
Btw, I believe that last semester’s students still have all their stuff in the Redis instances you guys are now using. Feel free to flush their work (the command is “FLUSHDB” at the Redis command line) before adding your stuff.
Here’s today’s XP-bearing activity if you want to practice with it before the quiz.
Btw, the full Bene Gesserit Litany Against Fear runs like this:
“I must not fear.
Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it has gone past, I will turn the inner eye to see its path.
Where the fear has gone there will be nothing. Only I will remain.”
— Dune, Frank Herbert
From today’s class, here’s our final version of the “Hobby Manager” app:
(To unpack a git bundle on your system, type “git clone nameOfGitBundle.git“.)
Quiz #5 is a 60-minute, closed-Python and closed-Redis affair that is due on April 2nd at midnight. Good luck!
Remember that you’ll need to do two things to connect properly to Redis on cpsc: authenticate with the password I gave in class today, and select the correct instance.
From the command line:
$ redis-cli 127.0.0.1:6379> auth theClassPassword OK 127.0.0.1:6379> select yourInstanceNumber OK 127.0.0.1:6379[yourInstanceNumber]>
From Python:
import redis
r = redis.Redis(password="theClassPassword",
db=yourInstanceNumber,
decode_responses=True, charset='utf-8')
From today’s class, the first cut at our “Hobby Manager” app:
(To unpack a git bundle on your system, type “git clone nameOfGitBundle.git“.)
As promised, assignment #7 has arrived and is due next Friday. Good luck, and happy coding!
Madelyn Maddie would appreciate it if you would take the time to complete this survey that she’s using as part of an independent study.
This year’s CPSC Programming Contest will take place on April 11th at 6pm! It involves free pizza, snacks, music, and fun! You should definitely mark this on your calendar if you haven’t already, and be sure to sign up with or without teammates. (You can indicate on the form if you’d like to be paired up on a team, and Ian, the contest maestro, will assign you companions.)
Additionally, I will award extra credit for all participants: +1XP for each problem your team gets correct. Also, any team that beats yours truly will receive the coveted opportunity to throw a whipped cream pie in my face in a public setting! This is a great way to humiliate me that you should be sure to take advantage of.
no class or office hours today (mar 20) – send email
From today’s class, the “final” versions of our SQLite-backed ice cream database:
(To unpack a git bundle on your system, type “git clone nameOfGitBundle.git“.)
Several people have asked me questions of the form “hey Stephen, have you graded my X yet?” Note that you can check this yourself by clicking on the “Details” tab of the scoreboard and entering your info. This will show you all the XP you’ve earned so far this semester, in all their glory.
The scoreboard has been updated with lots of stuff, including assignments 3 through 5, quiz #3, and the latest codingbat/leetcode points. Also, a sweet surprise for Stephen: nobody in the class managed to mess up the Honor pledge for quiz #3, which requires a clumsy email back and forth to correct! As a reward for this collective ability to follow instructions, everyone gets +1XP. Enjoy!
Also: props to kanarwithdamar, Lisan al-Gaib, P@$$WORD, GoldCannon, and suspiciouslyEven for reaching the “Chocolate Therapy” level, and to John Database for climbing up to “Minter Wonderland“!
Quiz #4 has been posted, and is due on March 18th at midnight. It contains no material from today (or even anything post-spring-break, actually) so fire away!
Okay, time to get excited!! The first milestone for your most excellent DB Tour project has been posted, and is due in little over a week. Get those creative juices flowing, and get cracking!! 
From today’s class:
(To unpack a git bundle on your system, type “git clone nameOfGitBundle.git“.)
Hmm. What I meant for you guys to turn in for your “assignment #4’s” was:
Instead, I’m getting lots of people whose “customer_service.py” file isn’t actually their customer service program at all, but appears instead to be their assignment #4 bulk-import code. I’m also getting people seem to have expected me to run their bulk-import code to populate their database with galactic stuff, instead of including an SQLite database that already has the galactic stuff included.
All this is taking me longer than I want to mess around with. And it has proven to be too onerous to try to dig up old assignment #3 submission emails, which may not even be compatible with any schema changes you had to make to accommodate galactic in assignment #4, etc.
**So, since I’m old and tired and want to make the process of grading 52 of these as streamlined as possible, I’m going to have everyone resubmit your assignment #3/#4 according to the above specifications. The subject line for the email should be “CPSC/DATA 350 Assignment #3/#4 resubmission”.
To be crystal clear: when I open your email, it should contain a git bundle as an attachment. When I clone that git bundle, I should then have (1) a customer_service.py file which does the whole assignment #3 thing, and which works on (2) your assignment #4 database file that contains all the galactic data. Also note: I will not be running any code to actually perform the bulk import; the results of that importing process should already be reflected in the database.
Submissions will be graded in the order they are received.
We’ve been working on localhost so much that I think I forgot to ever tell you guys how to get your Flask app running on the actual internet on the cpsc server. Duh.
The answer is, when you start Flask, do it this way:
$ flask run -h 0.0.0.0 -p yourPortNumber
The 0.0.0.0 is literal. The yourPortNumber” should be replaced with your port number.
From last week’s class:
(To unpack a git bundle on your system, type “git clone nameOfGitBundle.git“.)
Quiz #3 has been posted to Canvas, and is due after spring break. It’s a short one, timed at 30 minutes.
In case you want to get ahead over spring break, assignment #5 has been posted and is beckoning to you. It is actually due the Thursday after we get back.
At least one student has reported that if they include the “--skip-ssl” at the end of their connnection command, like this:
$ mariadb -u yourusername -pyourpassword -h cpsc.umw.edu -P 3306 galactic --skip-ssl
that it worked for him. Give it a shot if nothing else is working.
Here are my solutions to the extra credit activity that was due today.
I’ve been having so much fun that I sorta forgot that next week is spring break. 😀
So, here’s some important news regarding assignments 3 and 4:
A few implications for point #2, above:
If you’re having trouble reaching the galactic database, read carefully.
No rest for the weary — get ready for the impedance mismatch of the century: a bulk import assignment from mine to yours. It’s due next Sunday, and is not for the faint of heart. Happy importing!
From last week:
The “sample answer tables” I gave for each question in the extra credit activity are only intended to give the shape of the answer, not any actual answer on any particular database. Apparently I posted a previous version of my SQLite Ben & Jerry’s database at some point, and some students were entering their queries against that database and expecting to come up with the same numerical answers as on the activity. Do not expect this to be the case.
(Btw, I intended this activity to be a pencil-and-paper affair where you figured out the correct query by looking at the schema page we’ve been using in class, not a use-the-computer affair where you typed SQL queries at the SQLite prompt. I guess now that people are doing it that second way, I can’t really outlaw it, but it wasn’t my intent.)
From yesterday’s class, the code that used transactions so that multiple copies of it simultaneously accessing the same SQLite database didn’t interfere with each other in a destructive way.
You can earn up to +5XP by legibly writing queries to answer this set of questions. You are allowed to work in groups of up to 4 on this activity.
To claim these XP, turn in your legible solutions to my “350” manila envelope no later than 5pm, Monday 24. If you worked in a group, be sure to write everyone’s name on your submission.
For those of you following the SQLite formatting hassle, here’s today’s ChatGPT debugging session, which ended ambiguously.
From today’s class:
Taking the time to go through the rest of the questions on item #1 on your own would be an excellent and praiseworthy idea.
Assignment #3 has been posted, and is due next Sunday Feb. 23rd at midnight. Good luck!
A quick shout out to John Database and GoldCannon for being the first to reach the “Beet It” level!
Trivia question for the masses: what’s different about “Beet it” than any of the other semester’s levels?
A couple students asked a question about Item 9 on the quiz: why is the answer 5, not 4? The tables in question were PETS:
+----------------------+----------+----------+ | owner | dog | numYears | +----------------------+----------+----------+ | Laura Ingalls Wilder | Jack | 5 | | Veronica Mars | Backup | 3 | | Robert Barone | Chamsky | 9 | | Laura Ingalls Wilder | Bandit | 2 | | Fourth Doctor | K9 | 4 | | Sarah Jane Smith | K9 | 8 | | Raj Koothrappali | Cinnamon | 5 | | Emily Elizabeth | Clifford | 6 | +----------------------+----------+----------+
and CHARACTERS:
+-----------------------------+----------------------+-------+ | show | character | debut | +-----------------------------+----------------------+-------+ | Little House on the Prairie | Laura Ingalls Wilder | 1974 | | Clifford the Big Red Dog | Emily Elizabeth | 2000 | | Doctor Who | Fourth Doctor | 1974 | | Doctor Who | Sarah Jane Smith | 1973 | | The Mandalorian | Greef Karga | 2019 | +-----------------------------+----------------------+-------+
The query in question was this:
select count(*) from pets join characters on owner=character;
The students asked, “why doesn’t this give you 4 rows, since table rows must be unique and therefore Laura Ingalls Wilder can’t appear twice?”
But realize that this query isn’t a “select owner” or “select distinct(owner)“; rather, it’s a “select *“. So therefore, you’re counting the entire number of rows returned by the join, not the number of distinct owner names (or any other attribute).
If you get rid of the count(*) and just use * to see the whole table of results, you get:
+----------------------+----------+----------+-----------------------------+----------------------+-------+ | owner | dog | numYears | show | character | debut | +----------------------+----------+----------+-----------------------------+----------------------+-------+ | Laura Ingalls Wilder | Jack | 5 | Little House on the Prairie | Laura Ingalls Wilder | 1974 | | Laura Ingalls Wilder | Bandit | 2 | Little House on the Prairie | Laura Ingalls Wilder | 1974 | | Fourth Doctor | K9 | 4 | Doctor Who | Fourth Doctor | 1974 | | Sarah Jane Smith | K9 | 8 | Doctor Who | Sarah Jane Smith | 1973 | | Emily Elizabeth | Clifford | 6 | Clifford the Big Red Dog | Emily Elizabeth | 2000 | +----------------------+----------+----------+-----------------------------+----------------------+-------+
As you can see: 5 rows, with no duplicate rows.
If you miss points on a quiz question that you clearly had correct, but simply entered in a different format than I was expecting, please don’t just accept the loss and sulk. Instead, tell me about it.
For example, suppose the answer to some question was:
stephen
but for your answer you entered:
"stephen"
Depending on the exact nature of the question, this is quite possibly just as “correct” an answer as the one the quiz was looking for, yet it will be marked wrong because it wasn’t expecting you to put quotation marks.
All such answers should be regraded, and you should tell me about them. (Note that this is not an open invitation for you to tell be about the individual items you legitimately missed because you put the wrong answer. Only the ones where your obvious intent was to give the correct answer, but differences in formatting choices got in the way.)
I thought this would have been obvious, I guess, but in case not: no, you are not permitted to use the SQLite command line while taking the quiz. (If you think about it, the quiz would be pointless if you could do that, since anyone who knew how to type could get the questions right, even if they knew nothing about databases. The quiz is testing your understanding of the material in class, not your ability to type.)
Unfortunately, I won’t be able to make my usual 11:30am-12:30pm office hours on Tuesday, Feb. 18th. I will be there for the 2-3:30pm block, though.
For quizzes, you are allowed to use all handouts from class, any “cheat sheets” or other things posted on the class website, etc. Basically, anything written down that you want to use is okay. The only things that are not okay are programs (like the Python command line, or ChatGPT.)
From today’s class:
From today’s class, the queries against the B&J database that (1) reviewed selects, wheres, froms, Cartesian products, and joins, and (2) introduced group bys, havings, order bys, limits, and offsets. (Whew!)
At the usual time, at the same link we’ll be using for class (see Canvas announcement).
Will we have class tomorrow? Yes! See Zoom link in Canvas announcement.
Is class mandatory? No, class is never mandatory. You are big boys and girls, and can come and go whenever you choose. If you don’t think you will benefit from being there, you are free to skip any class at all, including tomorrow’s.
If I don’t come, should I get the notes from a classmate? Yes, as always.
What if I don’t have the proper Zoom equipment? This situation should be exceedingly rare in the post-Covid age, but I will attempt to record tomorrow’s lecture and post it on Canvas for anybody who isn’t able to “come to class.”
Quiz #2 has been posted, and is due Saturday, Feb 15th at midnight. It’s timed at 45 minutes, and covers all the material from class and readings up through and including Tuesday Feb 11th’s class. Good luck!
Really? Where I come from there at least have to be a few flakes falling first.
Anyway, we’re holding to a good pace so far this semester, and I do not want to fall behind. And given past UMW history, my bet is that class is canceled for more than just tomorrow. So here’s the official dealio:
See you guys Wednesday, regardless!
From today’s class, the SQL code to recreate our bootstrapped database:
Assignment #2 has been posted, and is due next Thursday at midnight. Note carefully: this assignment will probably take a medium amount of time if your assignment #1 was pretty clean, but a large amount of time if your assignment #1 had lots of mistakes. (This is because you’ll need to fix all those mistakes — or use Stephen’s solution instead — for assignment #2.)
Here’s my solution to assignment #1. If you got less than 35XP or so for this assignment, I strongly suggest you carefully look over my solution, and perhaps use it instead of your own as a basis for assignment #2.
Quiz #1 has been posted to Canvas, and is due on Friday at midnight. It is open-book and open-notes, closed-other-humans and closed-AI-assistants-such-as-ChatGPT, and timed at 60 minutes.
Good luck!
Abe, a pilot in our class, just now told me that there is in fact an “AID-type thing,” which is called a tail number, and it’s written on the fuselage. Call it what you wish on your homework!
Walk-in tutoring is available for this class (and others)!
This may seem inconsistent, but it’s the law in Stephenworld: your database does need to know who flew last October 29th’s United 277, but it does not need to know what runway United 277 might have had reserved on that date — all that it needs to know about runway reservations is what runways are currently reserved. (In other words, information about flight crew assignments must be kept in perpetuity, whereas your database only needs to know what current flight has each runway reserved, if any.)
Clarifications around crew members:
I don’t know if there is something like this in reality (I’m sure there is, though) but we’re going to say that all physical airplanes have an “AID” (“airplane ID”) which is globally unique.
Clarification: when I say to “email me” (with questions, to turn in an assignment, etc.) I really do mean “email me” (to stephen _AT_ umw _DOT_ edu), not “send me a Canvas message” (which I normally do not see and do not read).
Assignment #1 has been posted, and is due a week from today at 5pm (not midnight) to the “350” manila folder hanging outside my office door. If you have any uncertainty about what any of the requirements mean, please be sure to ask! If you don’t ask, and misinterpret a requirement as a result, you’ll miss out on points that you might otherwise have received.
Procrastinate on this to your peril!
You can earn up to +2XP per week by spending 30 minutes (per week) completing codingbat.com problems. All you need to do to claim these points each week is send me an email on Friday of the given week with subject line “CPSC/DATA 350 codingbat XP“. In the body of the email, you should type “I spent 30 minutes this week working Python exercises on codingbat.com,” followed by the Honor Pledge and your full name as a signature.
Happy coding!
Your first graded assignment of the semester — getting used to Python or brushing out the cobwebs — has been posted, and is due Tuesday, Jan 21st at midnight. Send questions!
Okay everybody, it’s time to earn your very first XP (experience point) of the semester, which is not only admirable in itself but is also required in order to earn any other XP at all!
All you need to do is head over to the Scoreboard (see link at top of page) and add yourself as a new student. Be sure to choose a screen name that is super secret, that you have never used before, and that you will not reveal to anyone.
Greetings, Earthlings, and welcome to the spring 2025 version of CPSC/DATA 350: Applications of Databases with Stephen! This site is gonna be hip-hoppin’ with all kinds of great stuff real soon, so stay tuned!
CPSC 350
