Interview Questions
MongoDB is a NoSQL, document-oriented database designed for scalability and flexibility. It stores data in JSON-like documents with dynamic schemas, making the integration of data in certain types of applications easier and faster.
A document in MongoDB is a set of key-value pairs. Documents are similar to JSON objects and are the basic unit of data in MongoDB. Each document contains a unique identifier, called the _id field.
A collection in MongoDB is a group of documents. It is equivalent to a table in a relational database. Collections do not enforce a schema, so documents within a collection can have different structures.
Sharding is a method for distributing data across multiple servers. MongoDB uses sharding to support deployments with large data sets and high throughput operations. A shard is a single MongoDB instance that holds a subset of the database's data.
Replication in MongoDB involves synchronizing data across multiple servers. It provides redundancy and increases data availability. MongoDB uses a replica set, which is a group of MongoDB servers that maintain the same data set.
MongoDB ensures high availability through replica sets. In a replica set, one node is the primary node that receives all write operations, while secondary nodes replicate the primary node's data. If the primary node fails, an election is held to determine which secondary should become the new primary.
The aggregation framework in MongoDB is used to process data records and return computed results. It provides a way to perform operations like filtering, grouping, and transforming data. The framework uses a pipeline of stages, where each stage performs a specific operation on the data.
A capped collection is a fixed-size collection that maintains insertion order and automatically overwrites the oldest documents when it reaches its maximum size. Capped collections are useful for applications that require high-throughput insertions, like logging.
