Redis

官网：https://redis.io/

源代码：https://github.com/redis

Redis is an in-memory database that persists on disk. The data model is key-value, but many different kind of values are supported: Strings, Lists, Sets, Sorted Sets, Hashes, Streams, HyperLogLogs, Bitmaps.

MongoDB

官网：https://www.mongodb.com

源代码：https://github.com/mongodb/mongo

MongoDB旨在大型数据库。它是一款NoSQL数据库，具有以下特性：面向文档的存储、完全索引支持、复制和高可用性等。可以通过10gen获得商业支持。

支持的操作系统：Windows、Linux、OS X和Solaris。

mysql

源代码：https://github.com/mysql

MySQL Server, the world's most popular open source database, and MySQL Cluster, a real-time, open source transactional database.

SQLite

官网：https://sqlite.org/

源代码：https://www.sqlite.org/cgi/src/doc/trunk/README.md

开源的、跨平台的字符集转换库。可以在Linux系统上使用，也支持Windows等其他操作系统。

SQLite is a C-language library that implements a small, fast, self-contained, high-reliability, full-featured, SQL database engine. SQLite is the most used database engine in the world. SQLite is built into all mobile phones and most computers and comes bundled inside countless other applications that people use every day.