# 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.remote` : execute a query by HTTP

- `arq.qparse` : parse and print a query.

- `arq.update` : execute SPARQL/Update requests.

- `arq` : run a test set.

- `arq.rset` : transform result sets.

- `arq.qexpr` : evaluate and print an expression.

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 --help` prints 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.
- `--service URL` : Remote service location

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 queryFile` will print the SPARQL algebra for the query in SSE format.

### `arq.update`

Execute one or more SPARQL/Update requests.

SPARQL/Update is an update language based on SPARQL syntax.

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

### `arq.qtest`

Execute a test set. In the ARQ directory, `qtest --all` runs the whole ARQ test suite.

To run a specific test suite, use `qtest manifest`. See the working group page DAWG Testcases for details.

### `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 query using HTTP to contact a remote service:

- `--service URL` : The endpoint.
- `--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.

ARQ Documentation Page