Mongos router behavior in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find all documents in the 'users' collection using mongos.

MongoDB

db.users.[1]()

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

Aupdate

Bfind

Cinsert

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

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

Using update() or remove() which modify data, not retrieve.

The find() method retrieves documents from a collection. Mongos routes this query to the correct shards.

2fill in blank

medium

Complete the code to insert a document into the 'orders' collection via mongos.

MongoDB

db.orders.[1]({"item": "book", "qty": 3})

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

Afind

BdeleteOne

CinsertOne

DupdateOne

Attempts:

3 left

💡 Hint

Common Mistakes

Using find() which only reads data.

Using deleteOne() or updateOne() which modify or remove data.

The insertOne() method adds a single document. Mongos routes the insert to the correct shard based on the shard key.

3fill in blank

hard

Fix the error in the query to update the quantity of an order via mongos.

MongoDB

db.orders.updateOne({"item": "book"}, {$set: [1])

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

A{"qty": 5}

B{"qty": 5

C"qty": 5}

D{qty: 5}

Attempts:

3 left

💡 Hint

Common Mistakes

Missing closing brace or quote.

Not using quotes around the key.

The update document must be a valid object. {"qty": 5} is the correct syntax inside $set.

4fill in blank

hard

Fill both blanks to query documents where the shard key 'userId' equals 12345.

MongoDB

db.users.find([1]: [2])

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

A"userId"

B12345

C"orderId"

D67890

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field name like 'orderId'.

Using string instead of number for the value.

The query must use the shard key field name as a string and the value to match. Here, "userId" and 12345 are correct.

5fill in blank

hard

Fill all three blanks to update the 'status' field to 'shipped' for order with orderId 67890 via mongos.

MongoDB

db.orders.updateOne([1]: [2], {$set: [3]: "shipped"}})

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

A"orderId"

B67890

C"status"

D"qty"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong field names in filter or update.

Not quoting field names properly.

The filter uses "orderId" and 67890. The update sets the "status" field to 'shipped'.