Rizan ibrahim w2 database #16
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yunchen4
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yunchen4
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Hi Rizan,
Overall your assignment is good. There are some points that you need rework. I have made them explicit. Please let me know on Slack when you finish the rework so I can review it again.
Don't hesitate to contact me if you have any questions!
Week2/assignment/keys.js
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| await connection.execute(` | ||
| create table research_Papers ( | ||
| paper_id int auto_increment primary key, | ||
| paper_title varchar (100), | ||
| conference varchar (100), | ||
| publish_date date, | ||
| author_id INT, | ||
| foreign key (author_id) references authors(author_id) on delete CASCADE | ||
| ); | ||
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| `); |
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I saw you created two research_papers tables. One here and the other in relationships.js.
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i had to check twice u are right.im gonna fix it
| // | ||
| const authorMentorRows = await connection.execute(` | ||
| select a.author_name AS author, m.author_name AS mentor | ||
| from authors a | ||
| left join authors m ON a.mentor = m.author_id | ||
| `); | ||
| console.log("Author and their mentors:"); | ||
| console.table(authorMentorRows); | ||
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| // | ||
| const [authorPapersRows] = await connection.execute(` | ||
| select a.author_name, r.paper_title | ||
| from authors a | ||
| left join author_paper ap ON a.author_id = ap.author_id | ||
| left join research_papers r ON ap.paper_id = r.paper_id | ||
| `); | ||
| console.log("Authors and their research papers:"); | ||
| console.table(authorPapersRows); |
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Needs rework: These two questions are answered in joins.js file. However you missed one question: All research papers and the number of authors that wrote that paper.
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u are right thanks for comment i will fix it
| const [femalePaperCount] = await connection.execute(` | ||
| select count(*) as total_female_papers | ||
| from author_paper ap | ||
| join authors a ON ap.author_id = a.author_id | ||
| where a.gender = 'female' | ||
| `); |
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Needs rework: If several female authors contribute to the same paper, will the query count the same paper multiple times?
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I think so, but should I avoid it or what?
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Well, when I read this problem I feel like no duplicate papers - but I might be wrong. So if you encounter this situation in your future work, always check it with your PM 😉 It's like an edge case.
| select a.university, count(ap.paper_id) as total_papers | ||
| from authors a | ||
| join author_paper ap ON a.author_id = ap.author_id | ||
| group by a.university |
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Needs rework: If several authors from the same university contribute to the same paper, will the query count the same paper multiple times?
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