nested queries

[Nie@asu.edu]

folks,

It's seems that the Niagara Engine can not support nested queries.
So,
1). you need not group the query results. For example, you can output your
results just like this:

<result><name>Rao</name><researchInterest>AI</researchInterest></result>
<result><name>Rao</name><researchInterest>DB</researchInterest></result>

You need not group this two tuple into one tuple like this:

<result>
   <name>Rao</name>
   <researchInterest>AI</researchInterest>
   <researchInterest>DB</researchInterest>
</result>
  
2). if there is missing attributes in a result tuple, this tuple can be
ignored in your query result set. For example, for the 4th query of task2, if
a professor is interested in artificial intelligence or databases, but he(or
she) did not offer any courses, then you need not include this professor's
information (tuples) in your query result.

Nie