RDQL
====

    Andy Seaborne
    andy_seaborne@hp.com

Current home:

    http://www.hpl.hp.com/semweb/

RDQL is a query engine for Jena.  It provides the SquishQL language (see
the grammar file for exact details).  Please see the web site for latest details.

Command Line
============

Try:
    java -cp ... jena.rdfquery

Type of Model Source
====================

If not specified some other way (e.g. the command line), the FROM clause in
a query will identify an RDF model.  Additional, if the model URI ends
".nt" it is assumed to be an N-Triple file; if it is .rdf, it assumed to be
XML; if it is .bdb, it is assumed to be a file that is a BerkeleyDB
database in the same directory as the BerkeleyDB environment files.

BerkeleyDB
==========

Jena includes a persistent store based on BerkeleyDB, available from 
http://www.sleepycat.com/.  You will need to put the BerkeleyDB binaries where
the JVM can load them.

RDQL can be used with BerkeleyDB models.  To name the source in a query or
from the commandline, give the filename of the database: used this way, the
databases files must be in the same directory as the BerkeleyDB
environment.  When programmatically specified, there is no such restrictions.

SQL Persistent Storage
======================

Jena includes a flexible SQL store that can be used for a variety of different
storage layouts.  A number of database systesm can be used including Postgres,
MySQL and Interbase.  To use this, you will need JDBC set up on your machine for
the appropriate database system.

RDQL can b eused to query such databases.  The source is named via the "jdbc:" 
URI.


Test
====

# Internal test
java -cp ...  jena.rdfquery --test
# Query validation
java -cp ...  jena.rdfquery --test <test description file>

The normal test file is modules/rdf/regression/testRDQL/_control_  The test
run should be in the main directory (the single top level directory of the
zip file).

Support & Feedback
==================

I would like to hear any comments you have about RDQL.

RDQL, like the rest of Jena, comes with no commercial support.  I will do
what I can to answer any questions and fix any bugs.  We use the mailing
list jena-dev@yahoogroups.com (http://yahoogroups.com/group/jena-dev)
for Jena support.