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From Aristedes Maniatis <...@ish.com.au>
Subject entities with calculated fields
Date Thu, 15 Feb 2007 10:54:46 GMT
We are very close to a release of our software but we've hit a  
performance problem in our approach to displaying a list of records.  
We are fetching a list of courses and for each one showing the count  
of enrolments. To do that, we are performing a second stored query to  
do a count which is proving to be too slow since it requires a second  
trip back to the database for each row.

Is there a way to do this by creating runtime virtual entity which  
represents a database view including that count column? Or for that  
matter any other approach to this speed problem? Doing this as a raw  
SQL fetch would obviously be quite quick since we could do this in  
one SELECT statement including the embedded COUNT, but we'd rather a  
Cayenne friendly option.


Ari Maniatis





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