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From Guy Rouillier <guyr-...@burntmail.com>
Subject Select one set null instead of throwing exception
Date Mon, 05 Oct 2009 04:14:41 GMT
Currently, performing a single row select throws an exception if zero or 
  > 1 rows are returned.  While this is certainly workable, an 
alternative that would be easier on the programmer would be to set the 
result to null if no rows are found, and only throw an exception if > 1 
rows are found.

The documentation suggests doing a count to determine what situation you 
are in, then issuing the appropriate select once you know.  But that 
will result in an extra trip to the DB.  In a common scenario where you 
are querying a primary key, you know that you will get zero or one row 
back.  So rather than having to put the single row select into a 
try-catch block, a more natural paradigm would be to assign the result 
and then check the result for null.

-- 
Guy Rouillier

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