Anti-patterns to avoid in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find all documents in the collection.

MongoDB

db.collection.[1]()

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

Afind

Binsert

Cupdate

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using insert() instead of find() to get data.

Trying to use update() to retrieve documents.

The find() method retrieves documents from a MongoDB collection. Using other methods like insert() or update() will not return documents.

2fill in blank

medium

Complete the code to avoid the anti-pattern of fetching all documents when only one is needed.

MongoDB

db.collection.[1]({})

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

AfindOne

Bfind

Caggregate

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using find() when only one document is needed.

Using aggregate() unnecessarily for simple queries.

Using findOne() fetches only one document, which is efficient when you need a single result. Using find() fetches all documents, which can be slow and waste resources.

3fill in blank

hard

Fix the error in the query to avoid the anti-pattern of unindexed queries.

MongoDB

db.collection.find({ [1]: 'value' })

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

AunindexedField

BnonexistentField

CrandomField

DindexedField

Attempts:

3 left

💡 Hint

Common Mistakes

Querying on fields without indexes causing slow performance.

Using fields that do not exist in the collection.

Queries should use indexed fields to avoid slow scans. Using indexedField ensures the query uses an index, improving performance.

4fill in blank

hard

Fill both blanks to avoid the anti-pattern of large documents by projecting only needed fields.

MongoDB

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

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

Aname

Bpassword

Cemail

DlargeData

Attempts:

3 left

💡 Hint

Common Mistakes

Including sensitive fields like password in projections.

Fetching large fields unnecessarily.

Projecting only necessary fields like name and email avoids fetching large unnecessary data such as password or largeData, improving query speed and reducing memory use.

5fill in blank

hard

Fill all three blanks to avoid the anti-pattern of inefficient updates by using the correct update operator and filter.

MongoDB

db.collection.updateOne({ [1]: '123' }, { [2]: { [3]: 'newValue' } })

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

A_id

B$set

CfieldToUpdate

D$push

Attempts:

3 left

💡 Hint

Common Mistakes

Using $push instead of $set for single field updates.

Filtering by a non-unique field causing multiple updates.

Replacing the whole document instead of updating a field.

Use _id to filter the document uniquely. Use the $set operator to update only the specified field fieldToUpdate. This avoids replacing the whole document and improves efficiency.