NoSQL: MongoDB

NoSQL, which stands for 'Not Only SQL', represents a diverse category of database systems that are not based on the traditional relational model. They were designed to address the challenges of modern applications, such as handling large volumes of unstructured data, providing high performance, and scaling horizontally (i.e., by adding more servers). MongoDB is one of the most popular NoSQL databases. It is a document-oriented database, which means it stores data in collections of documents. These documents are in BSON format, which is very similar to JSON (JavaScript Object Notation). A key feature of MongoDB is its flexible schema. Unlike in a SQL database, where you must define the structure of your tables upfront, in MongoDB, documents within the same collection can have different structures. This makes it very easy to evolve your data model as your application's requirements change. Data in MongoDB is typically queried using a rich, JSON-based query language. You can filter documents based on field values, perform range queries, and even query data within nested documents and arrays. Because of its flexibility and scalability, MongoDB is often used in applications that require rapid development, such as content management systems, mobile apps, and real-time analytics. It pairs particularly well with Node.js, as the data format (BSON/JSON) maps directly to JavaScript objects, making it very natural for developers to work with.