On 21/01/2023 09:11, Steven Blanchard wrote:
Hello,
I would like to know if it is possible to perform a query with
tdb2.tdbquery on multiple tdb folder?
It is not possible.
It is possible to put several times the --loc argument in the command
line but in the results, I have only the triple matches to the 2nd folder.
That should be an error.
Could you file an issue please?
example with Order 1 :
```bash
apache-jena-4.7.0/bin/tdb2.tdbquery --loc Demo_2/ --loc Demo_1/ --query
demo.sparql
?s ?p ?o
<<http://example.org/#spiderman>>
<<http://www.perceive.net/schemas/relationship/enemyOf>>
<<http://example.org/#green-goblin>>
```
example with Order 2:
```bash
apache-jena-4.7.0/bin/tdb2.tdbquery --loc Demo_1/ --loc Demo_2/ --query
demo.sparql
?s ?p ?o
<<http://example.org/#spiderman>>
<<http://www.perceive.net/schemas/relationship/loveOf>>
<<http://example.org/#lois_lane>>
```
demo.sparql:
```sparql
SELECT *
WHERE {?s ?p ?o}
```
I would like that the data available in both folder are merged to form a
new default graph for the query.
There is tdb2:unionDefaultGraph true ; for all named graphs in one
database as the default graph.
You can also define a general dataset and include (union) graphs from
several other storage units.
Another way is to use federated query (SERVICE)
https://jena.apache.org/documentation/query/service_enhancer.html
(The two TDB folders can't simply be used together because the internal
ids were allocated in such a way that they will overlap).
Andy
Thanks,
Regards,
Steven
