代写INFO20003 Semester 2, 2024 Assignment 2: SQL帮做SQL 程序

日期：2024-09-15 06:40

INFO20003 Semester 2, 2024

Assignment 2: SQL

Due: Week 8 - Sunday 15th September 2024, 5:59pm Melbourne Time.

Case: “Slarc” App

“Slarc”: Super Lovely App for Requesting Communications

Description

As fellow Database experts, DOTA2 fans, and enterprising communications fans, you and your classmates have created a new open source version of Teams/Slack called Slarc (inspired by the DOTA2 character and Slack!).

For each user, Slarc records their details such as an ID, a username, an email address, a login mechanism (which is defined strictly as one of the following: Google, Apple, Facebook, GitHub), and a reputation score (which is an integer from 0-100 inclusive, 100 as highly trustworthy and 0 being highly untrustworthy). Users can also upload an image for their avatar.

Users communicate with each other by posting in channels. Each channel has an ID, name, date of creation and optional description. When a user posts in a channel, Slarc tracks the post’s author, content and date of creation. Users can also post a reply to an existing post, or react to a post with an emoji, of which the reaction timestamp is recorded. There is an option for users to send attachments in a post; The system records the file size and the dataURL of the object. Slarc automatically scans each post for any harmful content, such as swearing and not safe for work material, and automatically restricts such posts. Similarly, it scans any attached files for potential viruses and flags the results.

When a user's reputation becomes greater than 80, they can be promoted to become a moderator. Other users will be able to see the date that a moderator was promoted, and their self-description if they choose to write one. Once one becomes a moderator, they can be appointed to moderate channels, usually endorsed by another moderator of the associated channel. Their date of appointment is also stored.

Moderators have the responsibility to ensure that posts in the channel abide by community guidelines. If they come across an inappropriate post or one that is flagged with restricted content, they will need to investigate and report on this case. For each case, the responsible moderator must record the case ID, give a brief explanation of the allegation and decide on whether it requires a consequential disciplinary action. The date of allegation will be automatically recorded. If a moderator decides that there needs to be a consequential action, then they can write down the associated action and its date; they are able to hide any post in the channel.

The Data Model

The Data Model from MySQL Workbench is provided in Figure 1.

FIGURE 1. DATA MODEL FOR SLARC.

Assignment 2 Setup

Please pay special attention to the penalties listed [⚠].

A dataset is provided which you can use when developing your solutions. To set up the dataset, download the file slarc.sql from the Assignment link on Canvas and run it in Workbench. This script. creates the database tables and populates them with data.

The sample dataset provided is a basic example of Slarc deployed for a DOTA2 e-sports community. You may find that you may need to add some more sample data in Workbench to fully test out each and every query.

Note that this dataset is provided for you to experiment with: but it is NOT the same dataset as what your queries will be tested against (the schema will stay the same, but the data itself may be different). This means when designing your queries, you must consider edge cases even if they are not represented in this particular data set.

The script. is designed to run against your account on the Engineering IT server (info20003db.eng.unimelb.edu.au). If you want to install the schema on your own MySQL Server installation, uncomment the lines at the beginning of the script.

⚠ WARNING: Do NOT disable only_full_group_by mode when completing this assignment. This mode is the default and is turned on in all default installs of MySQL workbench, and we’ve added a line to the top of slarc.sql to turn it on every time you run the script. in case you disable it! You can check whether it is turned on using the command `SELECT @@sql_mode`; The command should return a string containing ONLY_FULL_GROUP_BY or ANSI. When testing, our test server WILL have this mode turned on, and if your query fails due to this, you will lose marks.

The SQL Tasks

Please pay special attention to the penalties listed [⚠].

In this section are listed 10 questions for you to answer. Write one (single) SQL statement per question. Each statement must end with a semicolon (;). Subqueries and nesting are allowed within a single SQL statement – however, you may be penalised for writing overly complicated SQL statements.

⚠ WARNING: DO NOT USE VIEWS (or ‘WITH’ statements/common table expressions) OR VARIABLES to answer questions. Penalties apply.

❓The Questions

1. List all posts which contain no ‘react’s. Your query should return results of the form. (postPermanentID, text). (1 mark)

2. Find the most recently promoted mod (moderator) in the entire database. Assume there are no ties (only one is the most recent). Your query should return results of the form. (modID, username, dateModStatus). (1 mark)

3. List all posts created by user ‘axe’ that have at least 9000 views. Your query should return results of the form. (postPermanentID, viewCount). (1 mark)

4. Find the post which is most commented on (Hint: most ‘originalPostID’ appearances). If there are ties, then you must return all posts with the highest number. Your query should return results of the form. (postPermanentID, totalCommentCount), with one row per post in case of a tie. (2 marks)

5. List the dataURLs for all attachments to posts in channelNames containing ‘dota2’ (e.g., ‘dota2_players’, ‘info20003_better_than_dota2’). Your query should return results of the form. (dataURL, channelID). (2 marks)

6. Find which channel has the highest number of ❤s made to posts within the channel. (Hint: ❤s are simply ‘love’ found in the emoji ENUM). If there are ties, then you must return all results. Your query should return results of the form. (channelName, heartCount), with one row per channel in case of a tie. (2 marks)

7. Find the names of controversial users: defined as users who have < 60 reputation, have at least 1 moderatorreport on one of their posts, and at least 3 ‘love’ react’s given to their posts in total. Your query should return results of the form. (userID, reputation, totalModeratorReports, totalLoveReacts). (2 marks)

8. List the top 3 channels with the largest number of posts with attachments identified with virus(es). Also return the total count of such attachments for each channel. Your query should return results of the form. (channelID, channelName, totalVirusInfectedAttachments). If there are ties in the top 3 positions, you must return all ties. For example, let’s say the database contains seven channels and the ‘total number of virus-afflicted posts’ for each channel are (5, 4, 4, 3, 3, 2, 1). The top 3 counts are 5, 4 and 3 so you need to return the top 5 rows, which are the ones having attachment counts of (5, 4, 4, 3, 3). (3 marks)

9. We’ll use the term ‘repeater’ to describe a user who has had posts in more than one channel reported. Find moderators, and determine how many ‘disciplinary actions’ (as per the disciplinaryAction flag) they’ve given to ‘repeater’ users. Your query should return results of the form. (modID, numberOfDisciplinariesToRepeaters). (3 marks)

10. Find users who have not posted (or commented on any post) before 01/04/2024 in the channel ranked_grind, but have posted at least one COMMENT (a post which is a reply to another post) in dota2_memes on or after 01/04/2024. Your query should return results of the form. (userID) for all such users. (3 marks)

⚠ SQL Response Formatting Requirements

Please pay special attention to the penalties listed [⚠].

To help us mark your assignment queries as quickly/accurately as possible, please ensure that:

• Your query returns the projected attributes in the same order as given in the question and does not include additional columns.

o E.g., if the question asks, ‘return as (userId, name)’, please write SELECT userId, name …

o ⚠ DO NOT return attributes in the WRONG order, e.g., SELECT name, userId…

o You can name the columns using `AS` however you’d like, only the order matters. E.g., this is fine: SELECT userId, name AS fullName

• Please do NOT use “databaseName.tableName” format.

o E.g., please write “SELECT userId FROM users…”

o ⚠ DO NOT provide the database name, e.g. SELECT userId FROM coltonc.users ….

• Ensure that you are using single quotes ( ' ) for strings (e.g. …WHERE name = 'bob'…)and double quotes ( " ) only for table names (e.g. SELECT name FROM "some table name with spaces"…).

o ⚠ Do NOT use double quotes for strings: …WHERE name = "bob"….

o ⚠ Do NOT use Microsoft Word ‘smart quotes’ (the fancy ones as you see in “this” ‘example’).

• Comments are optional, but we recommend writing them for complex queries.

• ⚠Do NOT delete the special comment markers in the SQL template file. These include: -- BEGIN QX, -- END QX, and -- END OF ASSIGNMENT (where X is the question number). They help us mark your submission so tampering with them will hinder our marking and will attract penalties.