H2 is an embeddable RDBMS written in Java.

A fast and versatile ETL tool that can transfer data between RDBMS and NoSQL seamlessly

AI on the way. An auto deep learning pipe dream. An RDBMS approach to deep learning. Declarative, explainable, scalable, optimizable, easy to deploy, all that good stuff.

Virtuoso is a high-performance and scalable Multi-Model RDBMS, Data Integration Middleware, Linked Data Deployment, and HTTP Application Server Platform

Statically typechecks a common SQL dialect and translates it to various RDBMS backends

KunlunBase is a distributed relational database management system(RDBMS) with complete NewSQL capabilities and robust transaction ACID guarantees and is compatible with standard SQL. Applications which used PostgreSQL or MySQL can work with KunlunBase as-is without any code change or rebuild because KunlunBase supports both PostgreSQL and MySQL connection protocols and DML SQL grammars. MySQL DBAs can quickly work on a KunlunBase cluster because we use MySQL as storage nodes of KunlunBase. KunlunBase can elastically scale out as needed, and guarantees transaction ACID under error conditions, and KunlunBase fully passes TPC-C, TPC-H and TPC-DS test suites, so it not only support OLTP workloads but also OLAP workloads. Application developers can use KunlunBase to build IT systems that handles terabytes of data, without any effort on their part to implement data sharding, distributed transaction processing, distributed query processing, crash safety, high availability, strong consistency, horizontal scalability. All these powerful features are provided by KunlunBase. KunlunBase supports powerful and user friendly cluster management, monitor and provision features, can be readily used as DBaaS.