db-jdo-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Wes Biggs <...@tralfamadore.com>
Subject Re: Issue 147: Unique deletion by query
Date Tue, 29 Nov 2005 12:32:35 GMT
Craig,

I favor the exception for this case.  The way we've defined setUnique, 
it acts somewhat like an assertion, and the semantic should remain the 
same for both execute and delete.

Regards,

Wes


Craig L Russell wrote:

> Hi Michael,
>
> Sounds good.
>
> I was thinking some more about this issue and would like some feedback.
>
> I think that we should make the query.execute and 
> query.deletePersistentAll methods as similar as possible, meaning that 
> they  both should throw an exception if the cardinality of the results 
> is not zero or one.
>
> I'll have a proposed wording for the specification later, but for now 
> let's go with the patch.
>
> Thanks,
>
> Craig
>
> On Nov 28, 2005, at 5:35 AM, Michael Watzek wrote:
>
>> Hi Craig,
>>
>> I have added a second patch to JDO-166. It adds a unique query to the 
>> array of INVALID_QUERIES which is supposed to throw a 
>> JDOUserException at deletePersistentAll because the number of 
>> affected rows in the database exceeds 1.
>>
>> Regards,
>> Michael
>>
>>> Hi Michael,
>>> I'd expect a JDOUserException to be thrown.
>>> The spec says
>>> <spec 14.6.11>
>>> void setUnique(boolean unique);
>>> A14.6.11-1 [When the value of the Unique flag is true, then the  
>>> result of a query is a single value, with null used to indicate 
>>> that  none of the instances in the candidates satisfied the filter. 
>>> If more  than one instance satisfies the filter, and the range is 
>>> not limited  to one result, then execute throws a JDOUserException.]
>>> </spec 14.6.11>
>>> I can add a similar description to the deletePersistentAll methods.  
>>> It might require the JDOUserException to be thrown before actually  
>>> deleting anything (the semantics of the method are such that a 
>>> select  needs to be executed against the datastore anyway before the 
>>> delete  occurs).
>>> Another alternative is to disallow the Unique flag for  
>>> deletePersistentAll. But that's not what I would choose.
>>> Craig
>>> On Nov 25, 2005, at 6:07 AM, Michael Watzek wrote:
>>>
>>>> Hi,
>>>>
>>>> I have a question concerning unique deletion by query:
>>>>
>>>> Assuming a unique JDO query would throw a JDOUserException in  
>>>> execute() because the result is not unique, would you expect a  
>>>> JDOUserException thrown in deletePersistentAll()?
>>>>
>>>> The spec does not require this and I'm not sure if we should add a  
>>>> negative test case checking this.
>>>>
>>>> Regards,
>>>> Michael
>>>>
>


Mime
View raw message