The modeling of a row of columns of result. Each row must be able to return
an object given a column name, in a way similar to how a java.util.Map would
act.
Returns the list of all the columns that are present in this Row.
This is an introspection method that allows for discovery at the time of
rendering the results. Otherwise, there are no starting points to tell us
what column names we can use to call getObject
Returns:
an Iterator of QName objects that each represent a column name.