OpenLink Virtuoso Universal Server
OpenLink Virtuoso Universal Server is an open source, web-based and command-line software project that provides a virtual database product, which offers transparent, real-time access to disparate data sources, such as ODBC, XML, Web Services and JDBC, as well as transparent integration of disparate application logic like J2EE integration and Mono ECMA-CLI.
Offers web, file, and SQL database server functionality
OpenLink Virtuoso Universal Server's broad protocol support enables it to offer web, file, and SQL database server functionality alongside native XML storage, and Web services platform functionality as part of a cohesive single server solution. In addition, it supports SPARQL embedded into SQL, which can be used for querying RDF data that is stored in Virtuoso's database.
It features a unique hybrid server architecture that comprises of relational data management, XML data management, RDF data management, linked data server, document web server, text content management, web application server, full-text Indexing, as well as web services deployment.
Under the hood and availability
OpenLink Virtuoso Universal Server is a cross-platform software that can be used on all mainstream operating systems, including GNU/Linux, Microsoft Windows and Mac OS X. It is written in the C and PL/SQL (Procedural Language/Structured Query Language) programming languages and designed to run on a console/terminal environment.
The software is available for download as a universal sources tarball that can be installed on virtually any Linux kernel-based operating system, as well as on Mac OS X, BSD, Solaris and Microsoft Windows OSes. It can be easily administer using its powerful and user-friendly web-based interface. Both 32-bit and 64-bit instruction set architectures are supported at this time.
Open Source and Commercial editions
This is the open source edition of OpenLink Virtuoso, but the project is also distributed as a commercial edition that includes even more features and paid support for small and medium-sized business. Prices start from 100 bucks for the latest version of OpenLink Virtuoso for Linux, Macintosh or Windows platforms. See the project’s homepage (link below) for more details.