***CAUTION***
If you are installing over older version (below 0.50), you will need to re-create your storages (both DB_File and Postgres).
This is the README file for RDF::Core, a package for handling RDF data.
RDF::Core is a pure perl implementation of RDF storage, parser, serializer and query.
The storage functionality is basic - store, delete, query statements, where query means ask about existence or count or retrieve statements conforming given mask of (subject, predicate, object). Three storages are available - in memory, file (DB_File) and DBMS (PostgreSQL).
The parser supports full RDF/XML syntax including aboutEach attribute (though it became obsolete). The serializer attempts to preserve anonymous nodes and to compact xml a bit grouping statements with common subject.
The query language is rather focused on resources than on statements. The typical pattern is me->neighbor->child->age to express neighbour's children's age, not (me,neighbour, him) && (him, child, it) && (it, age, value). It contains some shortcuts to express things, that are (possibly) expressed often, like object->rdf:type = someClass. Functions are another enhancement of the language. They can be used instead of resource or property. Functions are implemented in a separated library, so that it's easy to create new or modify existing ones.
Original creator of RDF::Core is Ginger Alliance (www.gingerall.com).
RDF::Core is an Open Source project released under the MPL (Mozilla Public License). Alternatively you may use RDF::Core under the GNU's GPL license.
Please, look at http://www.mozilla.org/MPL or http://www.gnu.org/copyleft/gpl.html for further info.
We offer NO WARRANTY for using RDF::Core in any conditions.
You need XML::Parser, version 2.3 or above and URI 1.03 or above to install RDF::Core. Optionally you need DBI (1.14) if you want Postgres data storage and DB_File (1.72) for file data storage.
perl Makefile.PL
make test
make
make install (may require the root privileges)
DBMS storage installation (optional):
Create a PostgreSQL database.
Load PL/pgSQL procedural language.
Change working directory to ./dbmodel/pgsql
Execute sql script in rdf-pgsql.sql
Of course, we're not able to test it on all Unix machines, so if you meet any problem, feel free to contact us.