Exercises

An exercises about find() operation

Exercise 1

Preliminary

• Import people.json into lab4.people (i.e. database name is lab4 and collection name is people)

$ mongoimport -d lab4 -c people people.json

Questions

• Find the documents whose age under 22.

• Find the documents whose age is between 22 and 26 (inclusive).

• Find the document whose name is “Lee” suppressing the profile.

• Find the documents whose name is not Lee.

• Find the documents whose name is “Lee” or “Park”.

• Find the documents whose name is not “Kim” or “Park” or “Lee”.

Exercise 2

Preliminary

• Import inventory.json into lab4.inventory

Questions

• Find documents where the tags field contains below elements.

  • appliance, school, and book.

  • Hint: recall $all operator

• Find all documents but select at most three items in the tags field.

  • Hint: recall $slice operator

• Find all documents but select items from the second to the fourth in the tags field.

  • Hint: recall $slice operator with [skip, limit]

• Find documents that have brown color in the qty field.

  • Hint: recall $elemMatch operator

Exercise 3

Preliminary

• Import store.json to the store collection

Questions

• Find documents where buyer's name is "J.S. Lee"

  • Hint: Querying embedded document.

• Print purchased items where a name in a document is "iPhone Xs"

  • Hint: Querying embedded document, Projection

• Print the buyer’s purchase method where items contain the document that price is more than 2000$

  • Hint: < array.field >, Projection

• Find documents that don’t have carrier as key in attribute where the name is "Apple Watch Series 4"

  • Hint: $elemMatch, $exists

Exercise 4

Preliminary

• Import store.json to the store collection

  • Same with Exercise 3!

Questions

• Find documents where buyer's name is "J.S. Lee"

  • Hint: Querying embedded document.

• Print purchased items where a name in a document is "iPhone Xs".

  • Hint: Querying embedded document, Projection

• Print the buyer’s purchase method where items contain the document that price is more than 2000$.

  • Hint: <array.field>, Projection

• Find documents that don’t have carrier as key in attribute where the name is "Apple Watch Series 4"

  • Hint: $elemMatch, $exists

Exercise 5

Preliminary

• Import store.json to the store collection

  • Same with Exercise 3!

Questions

• Get the first three documents and print buyers field only.

• Skip a document and then print two documents

• Count documents in the store collection.

Exercise 6

Preliminary

• Using grade.json (import it using mongoimport)

Questions

• The grade’s document can have among three types:

  • quiz, exam or homework

• Student id (sid) is from 0 to 99

• A document is lost, which contains a quiz score 1. print lost document’s sid. 2. Insert the quiz score (80) to the corresponding sid 3. print the three students that have the highest quiz score.

• A simple example of the dataset looks like ...

{"sid": 0, "type": "homework", "score": 69}
{"sid": 0, "type": "quiz" , "score": 29}
{"sid": 0, "type": "exam", "score": 86}
{"sid": 1, "type": "homework", "score": 2}
{"sid": 1, "type": "quiz" , "score": 6}
{"sid": 1, "type": "exam", "score": 67}
{"sid": 2, "type": "homework", "score": 13}
{"sid": 2, "type": "quiz" , "score": 91}
{"sid": 2, "type": "exam", "score": 76}
...

Exercise 7

Preliminary

• Using grade.json (import it using mongoimport)

  • Same with exercise 6

Questions

• Write the score searching script

  • Search documents by filtering type and score fields

Results

search > homework 13
sid homework
2 13
74 13

search > quiz 41-49
sid quiz
10 46
17 48
19 44
...
96 49
98 41