[Mulgara-dev] XSD Date/Time Corruption reproducible

Andrae Muys andrae at netymon.com
Sat Jan 27 06:50:56 UTC 2007


On 27/01/2007, at 4:29 PM, Paul Gearon wrote:
> On Jan 26, 2007, at 7:07 PM, Andrae Muys wrote:
>> Actually in discussion last night it occurred to me that this  
>> isn't going to work either.  This problem arose because localtime  
>> is not continuous.  The above proposal doesn't work because  
>> localtime isn't monotonic either.  Specifically there is no  
>> localtime lexical form for the last hour of DST - java assumes  
>> standard-time for ambiguous timestamps.
>>
>> I think we always have to use timezones, ie. option 1. isn't  
>> really an option.
>
> I disagree.  From a string representational point of view (which is  
> what toString() is all about) then the ambiguous time is just  
> fine.  That's EXACTLY what people see.  Internally the times are  
> just fine, and the system knows that 1:30am the first time through  
> is actually earlier than 1:15am the second time through.  It just  
> get printed in a funny way for people.  But it's *supposed* to.
>
> If it's important that it get printed in an unambiguous way, then  
> we provide the option for it.

Well I'm not convinced, so I will wait to see what other people say  
about this.


>> Moreover we also do need to think about adding a localtime  
>> datatype - one that actually stores a date/time rather than a  
>> timestamp.  This is important for issues such as calendar  
>> applications and event management where the location/timezone is  
>> stored independently of the date/time and the value cannot be  
>> represented as a time_t.  For now users who need to do this can  
>> reify their dates, but it would be nice to support them natively.
>
> I'm reluctant to add any datatype that is not in XSD.  For a start,  
> what is the datatype URL?  It won't be standard RDF.

I'm not aware of anything in RDF that mandates that a datatype URI  
has to be a XML Schema Datatype.  Yes XSD is important to support,  
but there are numerous other datatype standards out there, and it is  
perfectly legitimate to use them.  I am not the slightest bit  
hesitant to provide non-XSD datatypes - especially where the  
datatypes in question are not defined in XSD.

Andrae

-- 
Andrae Muys
andrae at netymon.com
Principal Mulgara Consultant
Netymon Pty Ltd





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