Hi Rainer, all,
On 3/11/2011 8:05 AM, Rainer Kwesi Schweigkoffer wrote:
> 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.
It does. However as the first of the above links demonstrates, at least one
major database thinks differently, and as far as I can tell not many databases
support it, so I don't see that as a critical factor for us.
Thus, if we decided to go for
> null, it might be worth pondering whether we really want to borrow the
> name from SQL.
I'm not wedded to the name, but it seems a good fit.
>
> Kind regards
> Rainer
>
>
>
>
>
>
> ---
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