Because operation, along with all of the non-virtual columns.
You create a virtual column based on an XML element or attribute by defining it in terms of a SQL expression that involves that element or attribute; that is, you create a function-based column. For example, if you are sure that a given source XML document is valid, you can provide an argument to the constructor that disables the type-checking that is otherwise performed.
In the absence of both the encoding declaration and the BOM, the XML entity is assumed to be encoded in UTF-8.
Because ASCII is a subset of UTF-8, ASCII entities do not require an encoding declaration.
Instead, you must create that represent the XML data of interest, and then use those virtual columns to define the constraints that you need.
This approach applies only to XML data that is stored as binary XML.
It is equivalent to the IANA registered standard UTF-8 encoding, which supports all valid XML characters.To load an XML document into the repository under a given path, use PL/SQL package Many operations for configuring and using Oracle XML DB are based on processing one or more XML documents.Examples include registering an XML schema and performing an XSL transformation.This chapter provides an overview of how to use Oracle XML DB.The examples here illustrate techniques for accessing and managing XML content in purchase orders.