[Mulgara-dev] Problem w/ "insert select ..."

[Eric Brown]

Hi Andrae,

On Mar 28, 2007, at 8:36 PM, Andrae Muys wrote:

>
> On 29/03/2007, at 11:08 AM, Eric Brown wrote:
>
>>
>> I also tried inserting into a different model -- same error. It  
>> also seemed like I should have been able to make the query simpler  
>> -- insert select $s <http://rdf.topazproject.org/RDF/ 
>> organizationType> 'bar' from <...> where $s <http:// 
>> rdf.topazproject.org/RDF/organizationType> 'foo' into <...> --   
>> but that's how I saw the error the first time and expanded it just  
>> in case mulgara was demanding variables instead of just tuples.
>>
>> I can open a JIRA issue, but I thought I'd double check that it  
>> isn't something stupid I'm doing first.
>
> This is a known bug, http://mulgara.org/jira/browse/MGR-43.  The  
> simpler query you mention is indeed the intended phrasing.

Okay, thanks. That's easy to work around in my case.

>> BTW, What I'm really need to do is insert followed by delete. It  
>> would be nice if ITQL had a "update select ..." or "replace  
>> select ..." ability.
>
> Neither update nor replace have any meaning when working with rdf.   
> Updating a _property_ of an _instance_ is an operation that only  
> makes sense when you have a concept of an _instance_ ---  
> correspondingly update is an rdfs level operation.  What mulgara  
> does provide is the concept of a transaction.  OTOH I would like to  
> see improved support for compound operations.  Something along the  
> lines of haskell's do syntax combined with a query/operation  
> monad.  I've been referring to this as let-expressions, but really  
> it about providing the ability to integrate side-effects (insert/ 
> delete) cleanly into sequences/sets of queries.

It'd be really nice if you could extend itql with very simple stored  
procedures (or even just functions defined on the current session).  
Of course things always start very simple...

Cheers,
Eric