XML data type stores a sequence of one or more XML element trees.
An XML document has one root element tree, which is treated by Sybase CEP Engine as a sequence of one XML element. However, the Sybase CEP XML data type can also store multiple elements, which are not joined by a single root. This is sometimes called an XML forest.
It can also store a value of NULL.
The Sybase CEP XML data type does not support comparison. Two XML values cannot be compared for equality or inequality. Thus XML cannot be used in places that require comparison. This precludes the use of the XML data type in a GROUP BY, ORDER BY, or PER clause and in the SMALLEST and LARGEST functions.
The XML data type uses the Infoset data model. This means that the structure of the tree is represented in the data model, but not the details of the string encoding. For example, <a></a> and <a/> are identical in Infoset.