Document size limits and structure rules in MongoDB - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the maximum size of a single MongoDB document?

MongoDB has a limit on how large a single document can be. What is the maximum size allowed for one document?

A 1 gigabyte (GB)

B 64 megabytes (MB)

C 16 megabytes (MB)

D 256 kilobytes (KB)

💡 Hint

Think about the BSON document size limit.

MongoDB limits each document to a maximum size of 16 MB. This is to ensure efficient storage and retrieval.

❓ query_result

intermediate

What happens if you try to insert a document larger than the limit?

You try to insert a document with size 20 MB into a MongoDB collection. What will be the result?

A The insert operation fails with an error about document size.

B The document is automatically split into smaller documents.

C The document is truncated to 16 MB and inserted.

D The insert succeeds without any error.

💡 Hint

MongoDB enforces strict size limits on documents.

MongoDB rejects documents larger than 16 MB and returns an error during insert.

📝 Syntax

advanced

Which document structure violates MongoDB rules?

Consider these four MongoDB documents. Which one violates MongoDB's document structure rules?

A { "name": "Carol", "age": 27, "address": { "street": "Main St", "city": "Town" } }

B { "name": "Bob", "age": 25, "$invalidField": "value" }

C { "name": "Alice", "age": 30, "_id": ObjectId("507f1f77bcf86cd799439011") }

D { "name": "Dave", "age": 22, "hobbies": ["reading", "sports"] }

💡 Hint

Field names starting with $ are reserved in MongoDB.

Field names in MongoDB documents cannot start with the dollar sign ($) as it is reserved for operators.

❓ optimization

advanced

How to store large files exceeding document size limit in MongoDB?

You need to store files larger than 16 MB in MongoDB. Which approach is correct?

A Use GridFS to split and store files in chunks.

B Compress the file and store it as a string in one document.

C Store the entire file as a single document with a large binary field.

D Split the file manually into multiple documents without using any special feature.

💡 Hint

MongoDB provides a special specification for large files.

GridFS is MongoDB's specification for storing and retrieving large files by splitting them into chunks.

🔧 Debug

expert

Why does this MongoDB insert fail with a 'BSONObjectTooLarge' error?

You run this insert command:

db.collection.insertOne({ "data": new Array(17000000).fill(0) })

It fails with a 'BSONObjectTooLarge' error. Why?

A The 'fill' method is not supported in MongoDB shell.

B MongoDB does not allow arrays as field values.

C The insertOne method requires a smaller batch size parameter.

D The array creates a document larger than 16 MB, exceeding the limit.

💡 Hint

Think about the size of the document created by the array.

The array with 17 million zeros creates a document exceeding 16 MB, causing the BSONObjectTooLarge error.