Usage
The client has many parameters, which describe what data needs to be downloaded, and how it needs to be converted. There are many ways to use the client, which are described in the following chapters.
Databus Client Parameters
-s, --source
Set the source you want to convert. A source can either be a [file/directory] to convert already existing files, or a [query file/query string/collection URI] to convert queried files. Notice that query files must have .sparql/.query as extension to be recognized.
-e, --endpoint
Set the sparql endpoint, where the query should be fired to. If you use a collection you don't need this parameter, because its detected automatically. Otherwise its mandatory.
-t, --target
Set the target directory for converted files
./files/
-c, --compression
Set the compression format of the output file
same
-f, --format
Set the file format of the output file
same
-m, --mapping
Set the mapping file for format-conversion to different format equivalence class
-d, --delimiter
Set the delimiter (only necessary for some formats)
,
-q, --quotation
Set the quotation (only necessary for some formats)
"
--createMapping
Do you want to create mapping files for mapped sources?
false
-g, --graphURI
Set the graph uri for mapping from rdf triples to rdf quads
-b, --baseURI
set the base URI to resolve relative URIs
-o, --overwrite
true -> overwrite files in cache, false -> use cache
true
--clear
true -> clear Cache
false
--help
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Queries
Various datasets are registered on the DBpedia Databus in the form of files. A query specifies an exact selection of these records of the DBpedia Databus to be processed by the Databus Client. Therefore, the query is one of, if not the most important parameter of the client.
Possible queries
You can pass any query that selects the object of the predicate databus:file, the name of the variable does not matter. The query should look like.
SELECT ?o WHERE { ?s databus:file ?o}
How to pass queries
There are three different ways to pass a query to the Databus Client:
Pass the query string directly as a parameter.
Note: this option does not work for CLI
Save the query in a file and pass the file path as a parameter.
The file extension of the query file must be
.sparqlor.query.
Collection URIs are also supported. The client receives the associated query itself.
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