Virtuoso is a scalable cross-platform server that combines SQL/RDF/XML
Data Management with Web Application Server and Web Services Platform
functionality.

Virtuoso is at the core a high performance object-relational SQL
database. As a database, it provides transactions, a smart SQL
compiler, powerful stored procedure language with optional Java and
.Net server side hosting, hot backup, SQL 99 and more. It has all
major data access interfaces, as in ODBC, JDBC, ADO .Net and OLE/DB.

Virtuoso has a built-in web server which can serve dynamic web pages
written in Virtuoso's web page language as well as PHP, ASP .Net and
others. This same web server provides SOAP and REST access to Virtuoso
stored procedures, supporting a broad set of WS protocols such as
WS-Security, WS-Reliable Messaging and others. A BPEL4WS run time is
also available as part of Virtuoso's SOA suite.