Hi Ivan,
thanks a lot for your proposal. It is almost identical to what I ended
up doing. Except for the last few lines where I used:
foreach(any row in rows) do
{
cnt := cnt + 1;
result(sprintf('sparql clear graph <%s>', row[0]));
if(state <> '00000')
signal(state, msg);
}
Should I rather use "sparql clear graph identified by iri(?:g)"?
Also is the "commit work" necessary?
Cheers,
Sebastian
On 11/24/2011 12:31 PM, Ivan Mikhailov wrote:
> Hello Sebastian,
>
> Consider this:
>
> create procedure nrl_drop_graphs(in query_base varchar, in query_params
> any := null)
> {
> declare stat, msg varchar;
> declare metas, rset any;
> stat := '00000';
> if (query_params is null)
> query_params := vector ();
> exec ('sparql ' || query_base, stat, msg, query_params, 1000, metas,
> rset);
> if ('00000' <> stat) -- If error state is set while the query is
> executed...
> signal (stat, msg); -- ...then we resignal it.
> if (1 <> length (metas[0]))
> signal ('?????', 'The query is supposed to return exactly one
> column, containing graphs to drop');
> foreach (any row in rset) do
> {
> declare g any;
> g := row[0]; -- The value of first (and the only) columns of row.
> if (__tag(g) in (__tag of varchar, __tag of nvarchar, __tag of
> IRI_ID))
> {
> sparql drop silent graph identified by iri(?:g);
> commit work;
> }
> else
> signal ('?????', 'Invalid graph IRI');
> }
> }
> ;
>
> A basic test is:
>
> sparql insert in graph <http://test1/> { <s1> <test> <o1> };
> sparql insert in graph <http://test2/> { <s2> <test> <o2> };
> sparql insert in graph <http://test3/> { <s2> <test> <o3> };
>
> sparql select * where { graph ?g { ?s <test> ?o} };
> --- Should return three rows.
>
> nrl_drop_graphs ('select ?g where { graph ?g { ?s <test> ?o }}');
>
> sparql select * where { graph ?g { ?s <test> ?o} };
> --- Should return zero rows because graphs are just dropped.
>
> Best Regards,
>
> Ivan Mikhailov
> OpenLink Software
> http://virtuoso.openlinksw.com
>
> On Wed, 2011-11-23 at 21:04 +0100, Sebastian Trüg wrote:
>> Hello list,
>>
>> I am trying to write a stored procedure which deletes a set of graphs
>> matching a query. This is what I have so far:
>>
>> create procedure nrl_drop_graphs(IN QUERY_BASE STRING)
>> {
>> DECLARE query STRING;
>> query := query_base + ' LIMIT 1000';
>>
>> declare cnt integer;
>> cnt := 0;
>>
>> while(1)
>> {
>> declare it cursor for sparql query;
>> open it;
>> declare v any;
>> while(1)
>> {
>> WHENEVER NOT FOUND goto done;
>> FETCH it INTO g;
>> vector_concat(v, g);
>> }
>> done: ;
>> close it;
>>
>> if(length(v)=0) return;
>>
>> for(any g in v)
>> {
>> cnt := cnt + 1;
>> sparql drop graph g;
>> }
>> }
>> }
>>
>> The idea is to get all the graphs in batches of 1000 and drop them one
>> by one since that is not possible with SPARUL (at least not in 6.1.4).
>>
>> It fails at the "declare cursor" since it is not happy with the
>> "sparql". This is the first time I try my luck with stored procedures so
>> the code may contains lots of stupidities. :P
>>
>> Thanks for your help.
>>
>> Cheers,
>> Sebastian
>>
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>
>
>
