What is a Key-Value Database?

A key-value database (sometimes called a key-value store) uses a simple key-value pair method to store data. These databases contain a simple string (the key) that is always unique and an arbitrary large data field (the value). These databases contain a simple string (the key) that is always unique and an arbitrary large data field (the value), making them a straightforward option for data storage. They are easy to design and implement, differing significantly from relational databases that organize data into tables and define data relationships between those tables.