Special character handling in SQL/XML publishing functions

SQL/XML publishing functions have a default behavior for handling special characters.

SQL values to XML values

Certain characters are considered special characters within XML documents, and must appear in their escaped format, using their entity representation. These special characters are as follows:

Table 1. Special characters and their entity representations
Special character	Entity representation
<	<
>	>
&	&
"	"

When publishing SQL values as XML values using the SQL/XML publishing functions, these special characters are escaped and replaced with their predefined entities.

SQL identifiers and QNames

When publishing or constructing XML values from SQL values, it can be necessary to map an SQL identifier to an XML qualified name, or QName. The set of characters that are allowed in delimited SQL identifiers differs, however, from those permitted in a QName. This difference means that some characters used in SQL identifiers will not be valid in QNames. These characters are therefore substituted with their entity representation in the QName.

For example, consider the delimited SQL identifier "phone@work". Because the @ character is not a valid character in a QName, the character is escaped, and the QName becomes: phone@work.

Note that this default escape behavior applies only to column names. For SQL identifiers that are provided as the element name in XMLELEMENT, or as a name in the AS clause of XMLFOREST and XMLATTRIBUTES, there are no escape defaults. You must provide valid QNames in these cases. Refer to the W3C XML namespace specifications for more details on valid names.