assignment2-questionnaire-answered.txt

UV Distributed Information Management - Questionnaire Assignment 2
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The purpose of this questionnaire is to deepen the student's understanding of
assignment 2 and the topics covered in the lecture. The main focus will be the
*correctness* and the *quality* of an answer, not its length. For some
questions, we will provide rough hints to make it easier for you.

You are free to answer the questions directly in this textfile or use another
editor/word processor. The following file formats will be accepted for the
submission: .txt, .pdf, .odt, .doc, .docx. Please note that other file formats
will result in 0 points (for this questionnaire). The preferred file formats are
.txt and .pdf (most word processors support an export as PDF file). In any case,
please make sure that the questions/answers are named/numbered properly!

This questionnaire will be discussed during the after-assignment meeting. Before
the meeting starts, the group will be informed about the preliminary points by
the instructor (either at the beginning of the meeting or via Blackboard). The
final points will be set after the meeting. This questionnaire contributes a
maximum of 8 points (2 points per answer) to the overall points of assignment 2.

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Question F1:
Formulate an SQL statement that is equivalent to your modified query Q3 of this
assignment.

Answer A1:

select count (*) from dblp 
join arxiv
on dblp.title = arxiv.title

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Question F2:
Familiarize yourself with the insertion of documents in MongoDB and insert a new
JSON document into the arXiv collection. The new document should have at least
one string value, one integer value, one array value, and one object value. The
content of the document is up to you and does not have to be a publication.

Hints:
https://docs.mongodb.com/manual/tutorial/insert-documents/

Answer A2:

db.arxiv.insertOne(
{ "id" : 7, "submitter" : "Group13", "authors" : "JK, KH, DG, VH", 
"versions" : { "version" : "v1", "created" : "Mon, 23 May 2022 19:00:00 GMT" },
"authors_parsed" : [ [ "K", "H", "" ], [ "G", "H", "" ] ]}
)

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Question F3:
Extend query Q2 such that it only reports publications authored by
"Michael Stonebraker" in books titled "ICDE" that are not co-authored by
"Samuel Madden". Please formulate the MQL query in the answer. For query Q2, we
refer to the assignment description. 

Hints:
In order to make AND conjunction and equality comparison explicit, query Q2 can
be rewritten as follows:
  db.dblp.find({
    $and: [
      { "author": { $eq: "Michael Stonebraker" } },
      { "booktitle": "ICDE" }
    ]
  }).pretty()

In this explicit notation, it should be easier to extend query Q2 as required.
Some other hints:
  - https://docs.mongodb.com/manual/reference/operator/query/and/
  - https://docs.mongodb.com/manual/reference/operator/query/eq/
  - https://docs.mongodb.com/manual/reference/operator/query/ne/

Answer A3:

db.dblp.find({ "author": {$ne: "Samuel Madden"},
    $and: [
      { "author": { $eq: "Michael Stonebraker" } },
      { "booktitle": "ICDE" }
    ]
  }).pretty()

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Question F4:
Familiarize yourself with updates of documents in MongoDB and update the JSON
document with id "1602.08791" of the arXiv collection as follows: Add a new
field that has "my_authors" as key and an array as value. The array should
contain two string values "Michael Stonebraker" and "Samuel Madden".

Hints:
https://docs.mongodb.com/manual/tutorial/update-documents/

Answer A4:

db.arxiv.updateOne( { "id": "1602.08791" }, 
	{ $set:{"my_authors": ["Michael Stonebraker", "Samuel Madden"]} })