What type of database is considered nonrelational and often used for documents?

A document database is a type of nonrelational database designed specifically to store, retrieve, and manage document-oriented information. This format allows data to be stored in a way that is more akin to how data is represented in applications, often using formats like JSON or XML to encapsulate the data within a document. Document databases enable flexible schema design, allowing fields to be added or modified without the need for a rigid structure, which is particularly beneficial for applications that require rapid iteration or have evolving data models.

In the case of document databases, they can efficiently handle various data types within a single document, which may include nested structures and arrays. This design caters well to use cases such as content management systems, blog platforms, or any application where unstructured or semi-structured data needs to be stored and accessed efficiently.

The other types of databases mentioned do not fit the criteria for storing documents in the same way. Key-value pair databases, for example, emphasize the storage of data in a simple key-value format, which is useful for caching or session storage but lacks the structure for complex documents. Structured databases, typically associated with relational database management systems (RDBMS), require a predefined schema that must be followed strictly, making them less flexible for document storage.