MongoDB Query Language: Beginner-Level Quiz

MongoDB Query Language Quiz

Welcome to the MongoDB Query Language quiz, a quiz designed to assess your understanding of the foundational concepts and best practices related to MongoDB, a powerful document-oriented NoSQL database. Let's get right at it!

1 / 20

Which MongoDB query is used to retrieve all documents from a collection?

db.collection.find()

db.collection.getAll()

db.collection.fetchAll()

db.collection.show()

2 / 20

What does the $push operator do in MongoDB?

Appends a document to the collection

Adds a value to an array field

Removes a value from an array field

Sorts the elements of an array field

3 / 20

How do you query for documents where a field value does not equal a specific value?

{ field: { $noteq: value } }

{ field: { $eq: value } }

{ field: { $ne: value } }

{ field: { $neq: value } }

4 / 20

What is the purpose of the $size operator in MongoDB queries?

To sort documents by their size

To match documents where an array field has a specific number of elements

To limit the number of documents returned

To find documents with a specific storage size

5 / 20

What is the primary reason developers use MongoDB?

Support for large SQL queries

Automatic report generation

Strict schema enforcement

Flexible schema and scalability

6 / 20

Which operator allows you to combine multiple conditions in a single query?

$in

$or

$merge

$and

7 / 20

How would you return only specific fields from a query result?

Using limit() on the query

By creating a compound index

Using the projection parameter in find()

Using the skip() function

8 / 20

What is the difference between $in and $nin operators?

$in matches documents containing specified values, and $nin matches documents that do not contain them

$in checks for numerical values, while $nin checks for non-numerical values

$nin is used for nested queries, while $in is not

$in is used for indexes, while $nin is used for aggregations

9 / 20

What does the $regex operator do in a MongoDB query?

Sorts the documents in ascending order

Joins two collections based on a pattern

Deletes documents with a matching field value

Matches documents where the field value satisfies a regular expression pattern

10 / 20

What is the purpose of the $exists operator?

To filter documents with non-empty fields

To check if a field exists or not in a document

To create new fields dynamically

To delete documents without specific fields

11 / 20

What does the limit() method do in a MongoDB query?

Restricts the number of documents returned

Sorts the documents in ascending order

Sets a timeout for query execution

Skips a set number of documents before returning the result

12 / 20

Which of the following is a key feature of MongoDB?

Predefined schemas and data constraints

Automatic SQL query optimization

Horizontal scaling through sharding

Native support for foreign keys

13 / 20

What does the $inc operator do in MongoDB?

Decreases the value of a field by 1

Replaces a field value with a new one

Increments the value of a field by a specified amount

Inserts a new field if it doesn’t exist

14 / 20

Which operator is used to match documents where a field value is greater than a specified value?

$gte

$lte

$eq

$gt

15 / 20

Which MongoDB query would you use to retrieve exactly 10 documents from a collection?

db.collection.find({ count: 10 })

db.collection.find().take(10)

db.collection.find().limit(10)

16 / 20

How would you find documents where a specific field contains a null value?

{ field: $null }

{ field: { $eq: null } }

{ field: $isNull }

{ field: null }

17 / 20

Which of the following queries uses the $or operator correctly?

{ $or: [ { field1: 'value1' }, { field2: 'value2' } ] }

{ $or: { field1: 'value1', field2: 'value2' } }

{ field1: 'value1' || field2: 'value2' }

{ $or: [ { field1: 'value1' }, { field2: 'value2' } ] }

18 / 20

What does the findOne() method return if no documents match the query criteria?

A MongoDB error

An empty array

Null

An empty document {}

19 / 20

How would you skip the first 5 documents in the query result?

db.collection.find().omit(5)

db.collection.find().jump(5)

db.collection.find().skip(5)

db.collection.find().ignore(5)

20 / 20

Which format does MongoDB use to store data?

CSV

BSON (Binary JSON)

Parquet

XML

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MongoDB Query Language (MQL) covers the syntax and functionality used to interact with and retrieve data from MongoDB.

The topic also explores how to sort, project, and limit query results, manage nested fields, and perform advanced operations such as joins using $lookup.

This quiz is designed for those with a basic understanding of MongoDB who want to deepen their skills in querying and manipulating data effectively for various application needs.