On 12/14/15 11:34 AM, Efimov, Alexander wrote: > > Hi Kingsley, > > > > The idea is that our concept model I map to with R2RML is not the same > as source tables. > > So just using output from Generate RDF Views would not work. > > I write custom R2RML code which maps from flat DB model to graph > concept model > > > > For example: > > > > Let it be the following tables: > > > > 1. Goods > > a. ID Integer > > b. Name String > > c. Category String > > d. SubCategory String > > > > 2. Customer > > a. ID Integer > > b. Name String > > > > 3. Order > > a. ID Integer > > b. Goods ID Integer > > c. Customer ID Integer > > > > These three tables map to our Concept model which is a bit different > from table structure and I’m executing SPARQL Query like this: > > > > PREFIX: sq:<http://our_schema> > > > > SELECT * > > FROM <http://this_is_the_graph_name <http://this_is_the_graph_name%20>> > > WHERE > > { > > ?customer sq:hasOrder ?order . > > ?order sq:hasGoods ?goods . > > ?goods sq:Name ?goodsName . FILTER (?goodsName in (‘Name1’, > ‘Name2’)) . > > ?goods sq:hasSubCategory ?subCategory . #note that subcategory is IRI > > ?subCategory a sq:SubCategory . > > ?subCategory sq:hasParentCategory ?category #note that category is IRI > > ?subCategory a sq:Category . > > }; > > > > In my particular case I map data from ~10 views to ~13 classes in our > concept model and WHERE statement is a bit longer. > > >
You have a number of rdf:type relations in your query which pose
problems unless you leverage the use of physical triples sync'd with
transient triples (the product of loading your r2rml mappings).
Command:
RDF_VIEW_SYNC_TO_PHYSICAL ('{virtual-triples-named-graph-iri}', 1,
'{physical-triples-named-graph-iri}');
Example:
Given a named-graph containing virtual triples (result of loading your
r2rml declarations) identified by the IRI
<http://demo.openlinksw.com/SQLServer#>, you could make the physical
sync replica using a named-graph that holds physical triples identified
by the IRI: <urn:demo.openlinksw.com:SQLServer> using the command:
RDF_VIEW_SYNC_TO_PHYSICAL ('http://demo.openlinksw.com/SQLServer#', 1,
'urn:demo.openlinksw.com:SQLServer');
Virtuoso will keep <urn:demo.openlinksw.com:SQLServer> in sync with
<http://demo.openlinksw.com/SQLServer#> and that named graph should be
the target of queries that are scoped to rdf:type relations.
Links:
[1]
http://kidehen.blogspot.com/2015/07/conceptual-data-virtualization-across.html
[2]
http://docs.openlinksw.com/virtuoso/fn_rdf_view_sync_to_physical.html .
--
Regards,
Kingsley Idehen
Founder & CEO
OpenLink Software
Company Web: http://www.openlinksw.com
Personal Weblog 1: http://kidehen.blogspot.com
Personal Weblog 2: http://www.openlinksw.com/blog/~kidehen
Twitter Profile: https://twitter.com/kidehen
Google+ Profile: https://plus.google.com/+KingsleyIdehen/about
LinkedIn Profile: http://www.linkedin.com/in/kidehen
Personal WebID: http://kingsley.idehen.net/dataspace/person/kidehen#this
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