The technique is as follows: data as you would create virtual columns using any other type of data, but using a slightly different syntax.In particular, you cannot specify any constraints in association with the column definition.In the absence of both the encoding declaration and the BOM, the XML entity is assumed to be encoded in UTF-8.
You exploit this structural knowledge to create virtual columns, which the database can then use with constraints.
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.
Figure 3-1 shows a simple drag and drop operation for copying the contents of the data.
It is equivalent to the IANA registered standard UTF-8 encoding, which supports all valid XML characters.