ARQ - Command Line Applications

The arq package contains some command line applications to run queries, parse queries, process result sets and run test sets.

You will need to set the classpath, or use the helper scripts, to run these applications from the command line. The helper scripts are in bin/ (Linux, Unix, Cygwin) and bat/ (Windows) directories. There are ancillary scripts in the directories that the main commands need - you should put the relevant directory on your command path and set the ARQROOT environment variable after checking these scripts are suitable.

• arq.query is the main query driver. It can be called for SPARQL, ARQ or RDQL queries and there are wrapper commands for each language: arq.sparql, arq.arq and arq.rdql.

• arq.qparse : parse and print a query.

• arq.update : execute SPARQL/Update requests.

• arq.remote : execute a query by HTTP on a remote SPARQL endpoint.

• arq.rset : transform result sets.

• arq.qtest : run a test set.

• arq.qexpr : evaluate and print an expression.

• arq.larqbuilder : Update a LARQ/Lucene index

• arq.larq : Query a LARQ/Lucene index

All commands have a --help command for a summary of the arguments.

When using a query in a file, if the query file ends .rq, it is assumed to be a SPARQL query. If it ends .arq, it is assumed to be an ARQ query (extensions to SPARQL) and if it ends .rdql, it is assumed to be an RDQL query. You can specify the syntax explicitly.

The commands jena.query, jena.sparql, jena.qtest and jena.rset are equivalent and just call to these commands.

arq.query

This is the main command for executing queries on data. The wrappers just set the query language.

• arq.sparql : wrapper for SPARQL queries
• arq.arq : wrapper for ARQ queries

Running arq.query --helpprints the usage message. The main arguments are:

• --query FILE : The file with the query to execute
• --data FILE : The data to query. It will be included in the default graph.
• --namedgraph FILE : The data to query. It will be included as a named graph.
• --desc/--dataset: Jena Assembler description of the dataset to be queried, augmented with vocabulary for datasets, not just graphs. See etc/ for examples.

The file extension is used to guess the file serialization format. If a data file ends .n3, it is assumed to be N3; if it ends .ttl is Turtle; if it is .nt is N-Triples; otherwise it is assumed to be RDF/XML. The data serialization can be explicitly specified on the command line.

arq.qparse

Parse a query and print it out. Can be used to translate between syntaxes (but not perfectly - specifically, RDQL value constraints need further conversion as complete mechanical translation is not possible).

arq.qparse will parse the query, print it out again (with line numbers by default) and then parse the serialized query again. If your query has a syntax error, a message is printed but no query is printed. If a query is printed then you get a syntax error message, then your query was syntactically correct but the ARQ serialization is broken.

The command arq.qparse --print=op --file <i>queryFile</i>will print the SPARQL algebra for the query in SSE format.

arq.update

Execute SPARQL Update requests.

• --desc: Jena Assembler description of the dataset or graph store to be updated. See etc/ for examples.

arq.rset

Read and write result sets.

In particular,

java -cp ... arq.rset --in xml --out text

will translate a SPARQL XML Result Set into a tabular text form.

arq.qexpr

Read and print an expression (something that can go in a FILTER clause). Indicates whether an evaluation exception occured.

The -v argument prints the parsed expression.

arq.remote

Execute a request on a remote SPARQL endpoint using HTTP.

• --service URL : The endpoint.
• --data FILE : Dataset description (default graph) added to the request.
• --namedgraph FILE : Dataset description (named graph) added to the request.
• --results FORMAT : Write results in specified format. Does not change the request to the server which is always for an XML form.

arq.larqbuilder

Build or update a LARQ index. If a dataset is given to the command, all graphs are indexed. if a single graph is given to the command, that graph is indexed.

• --larq : Name of the directory for the Lucene index files.
• --subjects : By default literals are indexed against the literal RDF node (pattern 1). Using this argument cause the subject RDF terms to be indexed (pattern 2).
• Dataset description using --data FILE or --desc.

arq.larq

Issue a Lucene query and print the nodes found (objects or subjects as appropriate).

• --larq : Name of the directory for the Lucene index files.