In the last few years non-relational data stores have drawn the attention of researchers and pratictioners. Their lack of fixed table schemas and the avoidance of join operators allow these tools to scale horizontally, storing huge amounts of data and providing high-performance access to it.
This class of databases (also known as NoSQL databases) often employs a distributed architecture with the data partitioned and redundantly replicated on several nodes, providing both scalability and fault tolerance.
