here is the relevant information from oracle web site
Escaping Characters in Generated XML Data
As specified by the SQL/XML standard, characters in explicit identifiers are not escaped in any way it is up to you to ensure that valid XML names are used. This applies to all SQL/XML functions; in particular, it applies to the root-element identifier of XMLElement (identifier, in Figure 17-1) and to attribute identifier aliases named with AS clauses of XMLAttributes (see Figure 17-2).
However, other XML data that is generated is escaped, by default, to ensure that only valid XML NameChar characters are generated. As part of generating a valid XML element or attribute name from a SQL identifier, each character that is disallowed in an XML name is replaced with an underscore character (_), followed by the hexadecimal Unicode representation of the original character, followed by a second underscore character. For example, the colon character (:) is escaped by replacing it with _003A_, where 003A is the hexadecimal Unicode representation.
Escaping applies to characters in the evaluated value_expr arguments to all SQL/XML functions, including XMLElement and XMLAttributes. It applies also to the characters of an attribute identifier that is defined implicitly from an XMLAttributes attribute value expression that is not followed by an AS clause: the escaped form of the SQL column name is used as the name of the attribute.
In some cases, you might not need or want character escaping. If you know, for example, that the XML data being generated is well-formed, then you can save some processing time by inhibiting escaping. You can do that by specifying the keyword NOENTITYESCAPING for SQL functions XMLElement and XMLAttributes. Keyword ENTITYESCAPING imposes escaping, which is the default behavior.
Main Topics
Browse All Topics
by: HainKurtPosted on 2009-11-04 at 18:26:10ID: 25746242
here is all info about auto escaping
http://download.oracle.com