XMLDB Internals: Non-recursive statement used during “SQL*Plus XQuery” statement

During a mind exercise with some of my OTN XMLDB forum peers, I discovered (tkprof…), that the non-recursive statement used for, for example the following:

SQL> xquery
  2   let $auction := ora:view("XTAB") return
  3   for $b in $auction/site/people/person[@id = "person0"] 
  4   return $b/name/text()
  5  /

is internally rewritten to

SQL> SELECT COLUMN_VALUE RESULT_PLUS_XQUERY FROM XMLTABLE
  2  ('let $auction := ora:view("XTAB") return
  3   for $b in $auction/site/people/person[@id = "person0"] 
  4   return $b/name/text()') 
  5 ;

So a “SELECT COLUMN_VALUE RESULT_PLUS_XQUERY FROM XMLTABLE()” wrapper statement is used as a replacement for the SQL*Plus “XQuery” command.

That explains, for instance, why the “heading” formatting as described in the 10gr2 manual regarding XQuery in SQL*Plus works.