Application Integration (Web Services & SOA)
Web Services
Why is Virtuoso described as a Web Services Platform?
It is described as such because it implements the complete stack of Web Services foundation protocols; SOAP, WSDL, and UDDI. It enables SQL Stored Procedures, Microsoft .NET, Mono, and Java based application logic to be invoked using SOAP. These SOAP compliant services are automatically described using WSDL, and advertised for binding via UDDI. This entire process is achievable without writing a single line of new code.
What is the benefit of Service Composition in Virtuoso
Exposure of existing time-tested application logic for invocation using Web Services protocols without any code re-writes. Code format support includes SQL Stored Procedures, .NET assemblies, Java Classes, C/C++ modules, etc.
What is meant by Service Invocation Endpoints?
Service Invocation endpoint are HTTP/WebDAV based virtual directory and multi-homing functionality that provides endpoints for SOAP-, WS-Security-, WSDL-, and UDDI-compliant interactions with composite services.
Content Management, WebDAV and HTTP Services
Can Virtuoso act as a repository?
Virtuoso can act as a repository through DAV, or WebDAV, which is a protocol for Web-based Distributed Authoring and Versioning. Repository content elements are called documents, corresponding to files, and folders/collections, corresponding to directories. Collectively these documents and folders (collections) are known as resources.
Virtuoso implements the DAV protocol, allowing you to create and manage resources either directly through repository manipulations or indirectly, through a variety of WebDAV services.
Can I host an Entire Web Site inside a VirtUoso Database?
Yes, as a HTTP/WebDAV compliant server all of the components within its WebDAV repository are URL and WebDAV protocol API accessible by HTTP/WebDAV compliant clients (user agents such as web browsers). The same applies to local operating systems files (subject to security controls of course).
Examples of WebDAV clients include the Windows (via Web Folders feature), Mac OS X, Nautilus Desktop (Linux and Solaris). An ever increasing pool web development tools and content management systems include in-built support for WebDAV.
Migrating your existing Web Site to one hosted by VirtUoso is as simple as using the VirtUoso HTML based UI to import the non VirtUoso hosted site.
What file transfer protocols does VirtUoso support?
Virtuoso has provided a built-in RFC-959/RFC-2389 Protocol Server for FTP as well as an FTP client since V3.2. VirtUoso FTP Client allows through VirtUoso PL code the ability to retrieve, submit and list files from any FTP server and stored the results on a local file system or in the database. The FTP Server provides FTP access to the VirtUoso WebDAV repository using the same authentication and permissions system as WebDAV.
Web Server
Does Virtuoso offer a Web application development language?
Yes, the Web application development language is called VirtUoso Server Pages (file extensions .vsp) and this can be used in conjunction with XML based server side control called VirtUoso Server Pages for XML (file extension .vspx). VSPX offers a suite of data bound controls for browsing and updating SQL data, input validation, session management and any other common web application development environment features.
XSLT can be used for pre- and post-processing VSPX pages. On the preprocessing side, it can serve to divide logic from layout by expanding simple markup into complex controls and scripting. On the output side it can be used to process the HTML generated by a dynamic web page to add HTML layout and graphic elements to bare-bones data produced by the business
Can Virtuoso be used as Search Engine?
Yes, like any search engine it possesses Free Text search capabilities that leverage its ability to produce Free Text indexes on all text data (SQL and non SQL). VirtUoso free text search includes word proximity searches, and the ability to combine XPATH, Free Text, and Regular Expressions, if required, in the same query. The long and short of this is that you can harvest and then index any form of text based web data (HTML, XHTML, XML etc.) stored in VirtUoso
What is Virtuoso's relevance is the world of XML?
It addresses the fundamental question; where is all the XML data going to come from? You can't exploit the benefits of XML without XML data, likewise you can't manually recreate XML data in an attempt to address this reality. VirtUoso enables you to create XML data from existing data sources such as your SQL databases. It also enables the creation of XML data from data external URL accessible data. An in-built XML validating XML parser and an XSL-T engine lie at the root of VirtUoso's XML Services offerings.
Does Virtuoso store XML Data Natively?
Yes, XML documents are stored in an XML repository. These documents may be parsed or unparsed at time of storage; in either case indexes are built which provide rapid access to these documents.
Why is XML Data Storage Important?
A major benefit of XML is its ability to provide an open format for data representation, exchange, protocol and application modeling. By using XML as a uniform data interface to disparate data sources, it becomes much easier to cost-effectively develop and deploy next generation web applications; increasingly these applications will depend on data hosted in a variety of databases and data sources.
Can I create Dynamic XML documents from SQL Data?
Yes, VirtUoso implements SQL extensions that enable the results of standard SQL queries to be transformed into XML documents, these documents are openly accessible to user agents such as Web Browsers via HTTP and/or WebDAV. It is important to note that these SQL-XML documents are URL accessible, and sensitive to the underlying changes that occur in the underlying database tables from which they have been derived.
Can Dynamic XML documents be built using SQL data from different databases?
Yes, the SQL to XML functionality sits above VirtUoso's virtual database functionality, which enables a unified logical and physical representation of database tables and views that reside in disparate database engines from different database vendors. The only requirement is that these databases have to be ODBC or JDBC accessible - implying the existence of data access drivers for these databases.
Which databases are supported by VirtUoso's SQL to XML functionality?
It supports any database that supports ODBC and/or JDBC, this implies pretty much every database.
Why is creation of XML documents from SQL important?
A lot of data that you would typically like to use as the foundation of your web application initiatives more than likely resides in application databases that are predominantly SQL based.
What WS-Security features are supported?
Virtuoso support of Web Services Security includes enabling the use of symmetric and asymmetric encryption, digital signing, and identity authentication as defined by the WS-Security specification
How does one test web services under Virtuoso?
Published SOAP Services can be tested through VSMX which is a Virtuoso generated test page which allows you to test SOAP Services. The SOAP Services can be referenced by the Server instances URL and the virtual directory containing the logical path of the services.
How do the XML schema based SOAP data types, SQL User Defined Types and hosted run time classes fit together?
How does one publish existing business logic via Web Services?
Business logic defined in stored procedures and functions can be exposed as SOAP services whether they are native VirtUoso or from remote data sources. These stored procedure can be published by linking the selected stored procedure through the Remote Procedure Interface, then creating a new or selecting an existing Virtual Directory and finally publishing to the Virtual Directory using the publish function in the Virtual Director User Interface.
What is the proven interoperability of the Virtuoso Web Services implementation as compared to other vendors?
Virtuoso participates in the SOAP Interop Forum and support level.