Free C100DEV Mock Exam – Practice Online Confidently

In a MongoDB database, you have a collection named orders that contains information about various product orders placed by customers. Each document in the collection has the following structure:{  "customerID": "",  "orderID": "",  "product": "",  "quantity": ,  "price": ,  "date": "",  "status": ""}You are required to write an aggregation query that retrieves all orders placed by customers where the quantity of ordered items is greater than 100 and the status of the order is "delivered". Which of the following $match stages would you use to achieve this? Select the best option.

Suppose you're designing a MongoDB database for an online ticket booking system where millions of users can concurrently book tickets for various events. To maintain data consistency, you need to ensure that only one user can book a specific seat for an event at a time. Which MongoDB feature would you use to ensure data consistency in this high-concurrency situation?

You manage a MongoDB collection called inventory that stores documents for a store's inventory. Each document has the fields item, category, and quantity. You want to ensure that an item is always present in the collection, even if it needs to be inserted. Specifically, if the item "notebook" in the "Stationery" category does not exist, it should be inserted with a quantity of 50. If it does exist, its quantity should be updated to 50. You plan to use the following command:db.inventory.updateOne(  { "item": "notebook", "category": "Stationery" },  { $set: { "quantity": 50 } },  { upsert: true })What will happen after executing this command if there is no "notebook" item in the "Stationery" category in the inventory collection?

You are designing a MongoDB collection to store information about books in a library. Each book document should contain the following fields:title: The title of the book (string).authors: An array of author names (array of strings).published_date: The publication date of the book (ISODate).categories: An array of categories or genres the book belongs to (array of strings).copies: An array containing details about each copy of the book, where each copy has an availability_status (string), location (string), and borrowed_date (ISODate) if the book is currently borrowed.Given this requirement, which of the following schemas correctly represents the document model for this use case? (Select two)

Which of the following constraints might impact your data model for MongoDB? (Select three)