sys_xmlgen takes an expression that evaluates to a particular row and column of the database, and returns an instance of type XMLType containing an XML document. The expr can be a scalar value, a user-defined type, or an XMLType instance.

By default the elements of the XML document match the elements of expr. For example, if expr resolves to a column name, then the enclosing XML element will be the same column name. If you want to format the XML document differently, then specify fmt, which is an instance of the XMLFormat object.