MongoDB Aggregation & Indexing Quiz

To modify existing documents

To perform complex data transformations and analysis

To store multiple collections in a database

To enforce schema validation

 $match

$group

$lookup

$sort

 Retrieves documents from another collection

Sorts documents in ascending or descending order

Filters documents based on conditions

Removes duplicate documents from the result

$filter

$match

$sort

 $project

Outputs results as a new collection

Displays results in a formatted way

Exports aggregation results to a JSON file

Removes specific fields from the output

Reduce storage space

Improve query performance

Increase document size

 Prevent duplicate records

db.collection.addIndex({ field: 1 })

db.collection.createIndex({ field: 1 })

db.collection.index({ field: 1 })

db.collection.ensureIndex({ field: 1 })

Single field index

Compound index

Text index

Multikey index

 The index is permanently removed

The collection is deleted

MongoDB rolls back to an older state

Queries become more efficient

 To store multiple indexes in one collection

To allow indexing on multiple fields

To create a separate collection for indexed fields

To convert numeric fields into indexed strings