Thanks Ivan,
2010/11/19 Ivan Mikhailov <[email protected]>:
> Hello Aldo,
>
> I'd suggest to use SQL BIFs sequence_next() and sequence_set(). Like any
> other functions without INOUT or OUT parameters, they can be called from
> SPARQL as bif:sequence_next() / bif:sequence_set()
>
> http://docs.openlinksw.com/virtuoso/fn_sequence_next.html
> http://docs.openlinksw.com/virtuoso/sequenceobjects.html
>
> For user-defined functions, an sql: prefix is better than bif: .
> sql:foo(x) will call DB.DBA.foo(x) . The difference is that bif:foo will
> create the call of unqualified foo(). If no built-in function foo()
> exists and the system contains many users and database qualifiers, the
> search for exact name of XXX.YYY.foo() may consume nonzero time (taking
> all security bore-me into account).
It works perfectly and thanks for the clarification between bif: and sql:
Now, from my own set of observations, I have learnt to call procedures
in SPARQL this way:
select (bif:sequence_next(?s)) as ?id where { ?s ?p ?o } limit 1
Does that seem right?
Regards,
A
>
> Best Regards,
>
> Ivan Mikhailov
> OpenLink Software
> http://virtuoso.openlinksw.com
>
>
> On Fri, 2010-11-19 at 19:17 -0300, Aldo Bucchi wrote:
>> Hi,
>>
>> Problem
>> * I need to generate unique IDs from within Virtuoso ( unique only to
>> a given Virtuoso instance/cluster would suffice )
>> * I need to do this via SPARQL HTTP prior to issuing a SPARQL insert
>>
>> Current solution:
>> Create a table and procedure that keeps track of an incremental ID and
>> returns each ID only once.
>> Access this procedure via SPARQL HTTP by using the ( select (
>> bif:foo() ) as ?id where { ?s ?p ?o } limit 1 ) trick.
>>
>> Question:
>> Any suggestions?
>> - for a better way of generating uniques
>> - for a better way of accessing the procedure from SPARQL
>> ?
>>
>> Also. I understand that blank nodes provide similar functionality. But
>> how can I access the "last insert id"?
>>
>> Regards,
>> A
>>
>
>
>
--
Aldo Bucchi
@aldonline
skype:aldo.bucchi
http://aldobucchi.com/
