Why delete operations need care in MongoDB - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to delete all documents where the field "status" is "inactive".

MongoDB

db.collection.deleteMany({"status": [1] })

Drag options to blanks, or click blank then click option'

A"inactive"

B"active"

Ctrue

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string value.

Using the wrong field name.

Using deleteOne instead of deleteMany when multiple documents match.

The deleteMany method requires a filter object. To delete documents where the status is "inactive", you must specify {"status": "inactive"}.

2fill in blank

medium

Complete the code to delete a single document where the "username" is "guest".

MongoDB

db.users.[1]({"username": "guest"})

Drag options to blanks, or click blank then click option'

Aremove

BdeleteMany

Cdrop

DdeleteOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using deleteMany and deleting more documents than intended.

Using drop which deletes the entire collection.

The deleteOne method deletes only the first document that matches the filter. Here, it deletes one user with username "guest".

3fill in blank

hard

Fix the error in the delete operation to avoid deleting all documents unintentionally.

MongoDB

db.orders.deleteMany([1])

Drag options to blanks, or click blank then click option'

A{"status": "pending"}

B{}

Cnull

D[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using an empty filter and deleting the entire collection.

Passing null or an empty array as filter which causes errors.

Using an empty filter {} deletes all documents. To avoid this, specify a filter like {"status": "pending"} to delete only matching documents.

4fill in blank

hard

Fill both blanks to delete documents where "age" is greater than 30 and "active" is false.

MongoDB

db.users.deleteMany({"age": { [1]: 30 }, "active": [2] })

Drag options to blanks, or click blank then click option'

A"$gt"

Btrue

Cfalse

D"$lt"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "$lt" instead of "$gt" for age comparison.

Using string "false" instead of boolean false.

To delete users older than 30, use "$gt" (greater than). To check if "active" is false, use the boolean false.

5fill in blank

hard

Fill all three blanks to delete documents where "score" is less than 50, "passed" is false, and "grade" is "F".

MongoDB

db.results.deleteMany({"score": { [1]: 50 }, "passed": [2], "grade": [3] })

Drag options to blanks, or click blank then click option'

A"$lt"

Bfalse

C"F"

D"$gt"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "$gt" instead of "$lt" for score.

Quoting boolean false as a string.

Forgetting quotes around grade "F".

Use "$lt" to find scores less than 50, boolean false for "passed", and string "F" for grade.