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

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

2 / 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

3 / 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

4 / 20

How would you query documents where a field exists but is not null?

{ field: { $exists: true, $not: { $eq: null } } }

{ field: { $exists: true, $null: false } }

{ field: { $eq: !null } }

{ field: { $exists: true, $ne: null } }

5 / 20

Which format does MongoDB use to store data?

CSV

BSON (Binary JSON)

Parquet

XML

6 / 20

What does the $type operator do in a query?

Matches documents where a field is of a specific data type

Retrieves only text-based fields

Checks if a document is of a certain collection type

Casts a field value to a different type

7 / 20

What is the primary reason developers use MongoDB?

Support for large SQL queries

Automatic report generation

Strict schema enforcement

Flexible schema and scalability

8 / 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' } ] }

9 / 20

Which operator allows you to query documents that contain an array field with a specific value?

$exists

$elemMatch

$set

$group

10 / 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

11 / 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

12 / 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

13 / 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)

14 / 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()

15 / 20

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

$gte

$lte

$eq

$gt

16 / 20

How can you ensure that only distinct values are retrieved from a collection?

Using db.collection.find({ distinct: true })

Using the $unique operator

By creating a unique index

Using the distinct() method

17 / 20

Which of the following best describes MongoDB?

In-memory key-value store

Document-oriented NoSQL database

Relational Database Management System

SQL-based data warehouse

18 / 20

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

{ field: $null }

{ field: { $eq: null } }

{ field: $isNull }

{ field: null }

19 / 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

20 / 20

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

$in

$or

$merge

$and

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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.