Atlas data federation concept in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the data source for Atlas Data Federation.

MongoDB

db.[1].find()

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

AtempCollection

BlocalCollection

CexternalDB

DfederatedCollection

Attempts:

3 left

💡 Hint

Common Mistakes

Using a local collection name instead of the federated one.

Atlas Data Federation uses a federated collection name to query data across multiple sources.

2fill in blank

medium

Complete the code to filter documents where the field 'status' equals 'active' in Atlas Data Federation.

MongoDB

db.federatedCollection.find({ 'status': [1] })

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

A'active'

Bactive

C"active"

Dactive"

Attempts:

3 left

💡 Hint

Common Mistakes

Using unquoted strings which are invalid.

In MongoDB queries, string values must be enclosed in quotes. Single or double quotes are acceptable in JavaScript, but in JSON-like query objects, single quotes are not valid JSON. However, in MongoDB shell, single quotes are acceptable. Therefore, 'active' is the correct choice here.

3fill in blank

hard

Fix the error in the aggregation pipeline to group documents by 'category' in Atlas Data Federation.

MongoDB

db.federatedCollection.aggregate([ { $group: { _id: [1], count: { $sum: 1 } } } ])

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

A"$category"

Bcategory

C"category"

D{category}

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the $ prefix, using unquoted field names, or literal strings without $.

The _id field in $group stage must use the field path "$category" to group documents by the category field.

4fill in blank

hard

Fill both blanks to project only 'name' and 'email' fields in the Atlas Data Federation query.

MongoDB

db.federatedCollection.find({}, { [1]: 1, [2]: 1 })

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

Aname

Bemail

Cstatus

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Including wrong fields or forgetting to set fields to 1.

Projection specifies which fields to include by setting them to 1 in the second argument of find().

5fill in blank

hard

Fill all three blanks to sort the federated data by 'createdAt' descending and limit results to 5.

MongoDB

db.federatedCollection.find().sort({ [1]: [2] }).limit([3])

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

AcreatedAt

B-1

C5

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of -1 for descending or wrong limit number.

Sorting by 'createdAt' descending uses -1, and limit specifies how many documents to return.