On 11/24/2011 01:31 PM, Ivan Mikhailov wrote:
> Sebastian,
>
> On Thu, 2011-11-24 at 13:16 +0100, Sebastian Trüg wrote:
>> 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?
>
> result() will not execute the query and will not set "state" or "msg"
> variables.
Sorry, I pasted a test version, I used exec() here instead of result(). :)
> commit work is not necessary for small number of small graphs, but many
> big graphs may exceed transaction log limit size.
OK, makes sense. Thank you.
Cheers,
Sebastian
> Best Regards,
>
> Ivan.
>
>>
>> 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
>
>
>
