Roy,

<< SELECT _ID, _Name, _xGlyph FROM QSC
WHERE _ID IN (SELECT _fkQSCdetail FROM QSCxRef WHERE _fkQSCmaster = :xref) >>

There will be an optimization in EDB for this soon.  EDB will essentially be able to reverse-project the condition in situations where the number of rows in the outer query is much, much greater than the number of rows in the sub-query.

Tim Young
Elevate Software
www.elevatesoft.com