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, OS/X) and bat/ (Windows) directories. There are ancillary scripts in the directories that the main commands need - see the tools page for setup details.

The commands look for file log4j2.properties in the current directory, as well as the usual log4j2 initialization with property log4j.configurationFile and looking for classpath resource log4j2.properties; there is a default setup of log4j2 built-in.

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). You can specify the syntax explicitly.

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.

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. Please report this.

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

arq.uparse

Parse a SPARQL update print it out.

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

arq.update

Execute SPARQL Update requests.

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 occurred.

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.