1. VoltDB：
VoltDB是分布式内存NewSQL RDBMS和使用无共享体系结构的ACID兼容RDBMS。该数据库由Michael Stonebraker，Sam Madden和Daniel Abadi设计。最初，VoltDB数据库包括群集吞吐量和延迟以及CPU和内存使用情况的图表。 VoltDB基于H-Store，并随着多核服务器上每CPU核心数的增加而扩展。
2. Virtuoso：
Virtuoso是一种中间件，支持对表示为关系表和/或属性图的数据进行管理。它是一个多模型混合型RDBMS ，它拥有主要数据库模型，如Graph DBMS，Native XML DBMS，Relational DBMS，RDF存储，搜索引擎。它旨在利用操作系统线程支持和多个CPU的优势。 Virtuoso对象关系数据库(ORDBMS)支持实体完整性和引用完整性。
VoltDB和Virtuoso之间的区别：
| S.No. | VoltDB | Virtuoso |
|---|---|---|
| 1 | Developed by VoltDB Inc. and initially released on 2010 and current release on April 2019. | Developed by Virtuoso and initially released on 1998 and current release on May 2019. |
| 2 | Its primary database model is Relational DBMS. | Its primary database model is Graph DBMS, Native XML DBMS, Relational DBMS, RDF store, Search engine and its secondary database models is Document store.. |
| 3 | It has Linux, OS X server operating systems. | Server operating systems of AIX, FreeBSD, HP-UX, Linux, OS X, Solaris, Windows. |
| 4 | VoltDB supports Java API, JDBC, RESTful HTTP/JSON API. | Virtuoso supports ADO.NET, GeoSPARQL, HTTP API, JDBC, Jena, RDF API, ODBC, OLE DB, RDF4J API, RESTful HTTP API, Sesame REST HTTP Protocol, SOAP, webservices, WebDAV, XPath, XQuery, XSLT. |
| 5 | Transaction concepts of VoltDB is ACID ( Atomicity, Consistency, Isolation, and Durability). | It has transaction concept- ACID ( Atomicity, Consistency, Isolation, and Durability). |
| 6 | Replication methods of VoltDB is Master-master replication and Master-slave replication. | Replication methods of Virtuoso is based on Chain, star, and bi-directional replication, Master-master replication, Master-slave replication. |
| 7 | It doesn’t holds sharding partitioning methods. | It doesn’t holds sharding partitioning methods. |
| 8 | It supports C#, C++, Erlang, Go, Java, JavaScript, PHP, Python programming languages. | Virtuoso supports .Net, C, C#, C++, Java, JavaScript, Perl, PHP, Python, Ruby, Visual Basic programming languages. |
| 9 | It doesn’t holds Consistency concept. | Yes, Virtuoso has Consistency concept. |
| 10 | Implementation language of VoltDB is Java, C++. | Implementation language of Virtuoso is C. |
| 11 | Absence of Foreign keys. | It has Foreign keys. |