RDFLib-SQLAlchemy
NOTE: This is a fork of the original rdflib-sqlalchemy. To install this fork instead of the original version with pip, use:
pip install rdflib-sqlalchemy-redux
A SQLAlchemy-backed, formula-aware RDFLib Store. It stores its triples in the following partitions:
- Asserted non rdf:type statements.
- Asserted rdf:type statements (in a table which models Class membership). The motivation for this partition is primarily query speed and scalability as most graphs will always have more rdf:type statements than others.
- All Quoted statements.
In addition, it persists namespace mappings in a separate table.
Back-end persistence
Back-end persistence is provided by SQLAlchemy.
Tested dialects are:
- SQLite, using the built-in Python driver or, for Python 2.5, pysqlite
- MySQL, using the MySQLdb-python driver or, for Python 3, mysql-connector
- PostgreSQL, using the psycopg2 driver or the pg8000 driver.
pysqlite: https://pypi.python.org/pypi/pysqlite
MySQLdb-python: https://pypi.python.org/pypi/MySQL-python
mysql-connector: http://dev.mysql.com/doc/connector-python/en/connector-python.html
psycopg2: https://pypi.python.org/pypi/psycopg2
pg8000: https://pypi.python.org/pypi/pg8000
Development
Github repository: https://github.com/RDFLib/rdflib-sqlalchemy
Continuous integration: https://travis-ci.org/RDFLib/rdflib-sqlalchemy/
An illustrative unit test:
import unittest
from rdflib import plugin, Graph, Literal, URIRef
from rdflib.store import Store
class SQLASQLiteGraphTestCase(unittest.TestCase):
ident = URIRef("rdflib_test")
uri = Literal("sqlite://")
def setUp(self):
store = plugin.get("SQLAlchemy", Store)(identifier=self.ident)
self.graph = Graph(store, identifier=self.ident)
self.graph.open(self.uri, create=True)
def tearDown(self):
self.graph.destroy(self.uri)
try:
self.graph.close()
except:
pass
def test01(self):
self.assert_(self.graph is not None)
print(self.graph)
if __name__ == '__main__':
unittest.main()
Running the tests
This is slightly baroque because of the test matrix (PostgreSQL|MySQL|SQLite x Python2.5|2.6|2.7|3.2) ...
Using nose::
DB='pgsql' DBURI='postgresql+psycopg2://user:password@host/dbname' nosetests
Using tox::
DB='pgsql' DBURI='postgresql+psycopg2://user:password@host/dbname' tox -e py32
DB variants are 'pgsql', 'mysql' and 'sqlite'
Sample DBURI values::
dburi = Literal("mysql://username:password@hostname:port/database-name?other-parameter")
dburi = Literal("mysql+mysqldb://user:password@hostname:port/database?charset=utf8")
dburi = Literal('postgresql+psycopg2://user:pasword@hostname:port/database')
dburi = Literal('postgresql+pg8000://user:pasword@hostname:port/database')
dburi = Literal('sqlite:////absolute/path/to/foo.db')
dburi = Literal("sqlite:///%(here)s/development.sqlite" % {"here": os.getcwd()})
dburi = Literal('sqlite://') # In-memory