Graph lookup for recursive data in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a $graphLookup stage in an aggregation pipeline.

MongoDB

{ $graphLookup: { from: "employees", startWith: "$managerId", connectFromField: "[1]", connectToField: "_id", as: "reportingHierarchy" } }

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

Asubordinates

BemployeeId

CreportsTo

DmanagerId

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong field that does not reference the manager.

Confusing connectFromField with connectToField.

The connectFromField should be the field that holds the reference to the manager, which is managerId.

2fill in blank

medium

Complete the code to specify the field to match in the $graphLookup stage.

MongoDB

{ $graphLookup: { from: "employees", startWith: "$managerId", connectFromField: "managerId", connectToField: "[1]", as: "reportingHierarchy" } }

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

AmanagerId

B_id

CemployeeId

DreportsTo

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-unique field for connectToField.

Mixing up connectFromField and connectToField.

The connectToField is usually the unique identifier field, which is _id in MongoDB documents.

3fill in blank

hard

Fix the error in the $graphLookup stage by completing the missing field.

MongoDB

{ $graphLookup: { from: "employees", startWith: "$managerId", connectFromField: "managerId", connectToField: "_id", as: "[1]" } }

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

AreportingHierarchy

Bsubordinates

Cmanagers

DteamMembers

Attempts:

3 left

💡 Hint

Common Mistakes

Using a vague or unrelated field name.

Leaving the as field empty or incorrect.

The as field defines the name of the array field to store the recursive results. reportingHierarchy clearly describes the data.

4fill in blank

hard

Fill both blanks to complete the $graphLookup stage that limits recursion depth and filters results.

MongoDB

{ $graphLookup: { from: "employees", startWith: "$managerId", connectFromField: "[1]", connectToField: "[2]", as: "team" , maxDepth: 2 } }

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

AmanagerId

B_id

CemployeeId

DreportsTo

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the two fields.

Using unrelated field names.

The connectFromField is managerId and connectToField is _id to correctly link employees to their managers.

5fill in blank

hard

Fill all three blanks to create a $graphLookup stage that starts from a specific employee, connects fields correctly, and stores results.

MongoDB

{ $graphLookup: { from: "employees", startWith: "[1]", connectFromField: "[2]", connectToField: "[3]", as: "allReports" } }

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

A"$employeeId"

BmanagerId

C_id

D"$managerId"

Attempts:

3 left

💡 Hint

Common Mistakes

Not using quotes and $ in startWith.

Mixing up connectFromField and connectToField.

The startWith should be "$managerId" to begin from the manager field, connectFromField is managerId, and connectToField is _id.