Introduction to XML Virtual Documents
InterSystems IRIS® provides support for XML documents as virtual documents. A virtual document is a kind of message that InterSystems IRIS parses only partially. This kind of message has the standard production message header and the standard message properties such as ID, Priority, and SessionId. The data in the message, however, is not available as message properties; instead it is stored directly in an internal-use global, for greater processing speed.
InterSystems IRIS provides tools so that you can access values in virtual documents, for use in data transformations, business rules, and searching and filtering messages. For background information, see Using Virtual Documents in Productions.
When reading XML documents, InterSystems IRIS removes the XML declaration, all processing instructions, and all comments.
If the name of an element or attribute includes a period (.), InterSystems IRIS replaces that with a tilde (~).
For example, an XML element named My.Element appears as My~Element in InterSystems IRIS.
You can also work with XML documents as standard production messages. To do so, you can generate classes from the corresponding XML schema. For information, see Using XML Tools.
In some cases, it may be more efficient to use XML-enabled objects in productions instead of XML Virtual Documents. See “XML-Enabled Objects Compared to XML Virtual Documents” for more information.