db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Shreyas Kaushik <Shreyas.Kaus...@Sun.COM>
Subject Re: [jira] Commented: (DERBY-165) Droppping columns with ALTER TABLE errors out
Date Thu, 07 Jul 2005 04:25:08 GMT


Daniel John Debrunner wrote:

>Dag H. Wanvik wrote:
>
>  
>
>>Hi Daniel,
>>
>>
>>    
>>
>>>>>>>"DJD" == Daniel John Debrunner <djd@debrunners.com> wrote:
>>>>>>>              
>>>>>>>
>>    
>>
>
>  
>
>>DJD> Not sure it's the job of Derby to recognize syntax it does not
>>DJD> support/implement. How far would you take it, complete SQL standard, any
>>DJD> other common SQL?
>>DJD> (ALTER TABLE is probably not covered by the standard)
>>
>>It  is covered, even in SQL-92, but I agree covering the full
>>standard in the parser is quite a task and probably not worth the
>>effort. Would you recommend that we only recommend the syntax we do
>>support at any one time?  I notice we do throw a few
>>SQLState.NOT_IMPLEMENTED exceptions in the parser today, mainly
>>related to national character set. Are there some guidelines which
>>specify which "not implemented" syntax is currently recognized, but
>>rejected?
>>    
>>
>
>No. :-)
>
>National Character types were partially removed from Derby, or really
>disabled. Since there was a chance it would be added back in we didn't
>just delete all the code, but left it in for future folks to work on.
>One of the reasons it was disabled is that it wasn't clear that the
>existing Cloudscape implementation was in line with the SQL standard,
>especially with conversions to and from date time values. Rather than
>allow a possible non-standard implementation, that would have to be
>supported for several releases, it was disabled, with the assumption
>that if it was someone's itch they could resolve any SQL standard issues
>before re-enabling it. Given JDBC 4.0 finally adds these types to JDBC,
>it might have been the best solution, otherwise we would have had
>changes in behaviour, e.g. metadata changing from Types.CHAR to
>Types.NATIONAL_CHAR.
>
>Dan.
>  
>
So should the behaviour for thi particular thing be the way it is ? Or 
should the parser throw a not implemented exception ?
Or is this a feature for the to-do list ?

~ Shreyas

Mime
View raw message