What is a non-relational database?

The following are several common non-relational databases: MongoDB, HBase, Redis, CouchDB, Secondary and so on.

1, MongoDB:MongoDB is a document-oriented database that stores data in BSON (binary JSON) format. It supports rich query languages and indexes, and is suitable for storing a large number of structured or semi-structured data.

2.HBase:HBase is a distributed column storage system based on Hadoop, which is suitable for real-time reading and writing of large-scale data. It is usually used to build real-time analysis and search engines.

3.Redis:Redis is an in-memory data storage system that supports a variety of data structures, such as strings, hash tables, lists, etc. It is widely used in caching, message queuing and real-time data analysis.

4.CouchDB:CouchDB is a document-based database, which uses JSON format to store data. It supports multi-version concurrency control and allows offline operation, which is suitable for applications that need offline synchronization and distributed deployment.

5.Secondary: Secondary is a graphic database, which focuses on storing and processing graphic structures. It is suitable for applications that need to deal with complex relationships efficiently, such as social networks and recommendation systems.