XML values can be serialized to a character string and returned as values of VARCHAR or CLOB data types. This serialization can be used with any XML value such as documents, sequences, or atomic values.
The serialization of a document is its well-formed string representation. For a sequence, this is the serialization of its items with intervening white space. For atomic values, it is the canonical lexical representations of those values as described by the XML schema specification.
Values serialized in this fashion are returned to the client encoded in the session character set. If any of the characters cannot be represented in the session character set, an error is raised.