Hi Linda, all,
Linda DeMichiel, am 10 Mar 2011 hast Du um 10:45 zum Thema "[jsr338-experts] Re: query improvements: downcast" geschrieben :
> I think that to be consistent with the use of treat to provide filtering
> in the FROM and WHERE clauses that this would need to return null.
>
> To exclude products that were not books, the query could, for example,
> use the TYPE operator in the WHERE clause.
>
> You might find the following of interest on the null vs exception issue
>
> From the Oracle Database SQL Language Reference:
> http://download.oracle.com/docs/cd/E11882_01/server.112/e17118/functions218.htm#SQLRF06148
>
> From DB2:
> http://publib.boulder.ibm.com/infocenter/db2luw/v9r8/topic/com.ibm.db2.luw.sql.ref.doc/doc/r0023463.html
Though I tend to be in favour of the null since it seems to be more
powerful for usage in FROM and WHERE clauses, I have to admit that the
SQL 2003 standard requires the exception. Thus, if we decided to go for
null, it might be worth pondering whether we really want to borrow the
name from SQL.
Kind regards
Rainer
---
Rainer Schweigkoffer SAP AG Walldorf
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Technology Development Dietmar-Hopp-Allee 16
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