Hello ALex, > 1) While in isql I cannot display previous commands in history. The up key > button shows the famous ^[[A string. This happens only in isql. > In the terminal I can see the previous commands using the referred key button. > Is it possible to solve this? I think this is quite critical for me...
The ISQL should be built with readline/termcap or similar libraries in order to support the history. This can be set in the "configure" script invocation. > 2) How do I delete a graph (not just delete all the triples from it) ? > > The old command (i.e., sparql delete graph <>) probable does not work anymore. > The other command: soarql drop graph <>) gives me this message: > *** Error 22023: [Virtuoso Driver][Virtuoso Server]SPARUL_DROP() failed: > graph <http://....com> has not been explicitly created before > > What is the difference for an explicit graph? This choice also exists > in the conductor interface. CLEAR GRAPH <> clears the whole content of the graph and optimizes free-text index for it. That's all you need for any practical purpose, because Virtuoso is a quad store, it does not require any special procedures to create or drop a graph as something that can exists without triples in it. However, for compatibility with triple stores, CREATE GRAPH and DROP GRAPH acts as if they were really needed. I.e., if a triple-store-oriented client has made CREATE GRAPH x, it can make DROP GRAPH x later, with all related checks and error messages like "created already" or "mothing to drop". > 3) How to show all the graphs? > When I use: sparql select distinct ?g where{graph ?g {?s ?p ?o}}; gives > me no result. > However, the query: > sparql select count(distinct ?g) where{graph ?g {?s ?p ?o}}; gives me 8. > The conductor also shows correctly my graphs. We have a cheat with select distinct ?g where {graph ?g {?s ?p ?o}} We replace this query with select distinct ?g where {graph ?g {?s a ?t}} because it is orders of magnitude faster and all real-life graphs have rdf:type predicates. Best Regards, Ivan Mikhailov OpenLink Software http://virtuoso.openlinksw.com
