Interview Questions and Answers

MongoDB is a NoSQL database that provides high performance, high availability, and easy scalability. It stores data in flexible, JSON-like documents called BSON.

A MongoDB document is a JSON-like data structure composed of field-value pairs. Fields may contain other documents, arrays, and arrays of documents.

BSON is a binary representation of JSON-like documents that MongoDB uses to store data. It adds support for data types like Date and Binary that are not natively supported in JSON.

NoSQL databases are databases that provide a mechanism for storage and retrieval of data that is modeled in ways other than the tabular relations used in relational databases.

A collection in MongoDB is a group of MongoDB documents. It is equivalent to an RDBMS table.

ObjectId is a 12-byte identifier typically employed as the primary key in a MongoDB document. It consists of a timestamp, machine identifier, process ID, and a random incrementing value.

The `findOne` method in MongoDB is used to retrieve a single document that satisfies the specified query criteria. It returns the first document that matches the query.