Skip to main content

Python bindings for Neo4j graph database

Project description

Neo4j Python Bindings
========================

:synopsis: Access Neo4j graph database functionality from python code

Only tested with Neo4j 1.3 on OSX Snow Leopard, Python 2.6


Notice
------
This is a work in progress. Please let me know if stuff in this document fails or doesn't seem to be true.

Thanks much.


Installation
------------

Install JCC:

$ easy_install jcc

Download and unpack neo4j somewhere (http://neo4j.org/download/)
Currently only version 1.3 is supported

Set NEO4J_HOME environment variable to this download of Neo4j:

$ export NEO4J_HOME=~/downloads/neo4j-community-1.3


Enter the Neo4py package directory:

$ cd the/directory/with/this/readme

Build C++ wrappers with JCC:

$ python setup.py build

Install (may require sudo-ness):

$ python setup.py install


Run some tests:
$ python test/test_graph_core.py

Hopefully no errors! If there are, send me the tracebacks :)


Getting started
---------------

Simplest way is to use the 'global' graph.
>>> from neo4py import neo
>>> gdb = neo.init_graph('test-graph.neo4j')
>>> gdb.shutdown()

This global graph may be accessed from anywhere after being initialized with
>>> gdb = neo.get_graph()


Transactions
------------

Transactions are handled differently than in neo4j.py

>>> tx, created = gdb.get_tx()

If created is True, it is the responsibility of this scope to commit the transaction when done it:

>>> tx.finish(True) # success - commit changes to database
>>> tx.finish(False) # failure - rollback changes

>>> tx.success() # or .failure()
>>> tx.finish() # it doesn't matter if True of False is passed here -- it will be ignored


Nodes, Relationships and Properties (Beginning of fun stuff)
----------------------------------

** Not all syntax is neo4j.py compatible **


Creating a node:: (must be within a transaction!)

>>> n = gdb.node()

Specify properties for new node::

>>> n = gdb.node(petals=5, color="Red", height=5.5) #support for number or string array properties is not yet added

Accessing node by id:

>>> n = gdb.nodes[14]


Accessing properties:

>>> value = n['key'] # Get property value

>>> n['key'] = value # Set property value

>>> del n['key'] # Remove property value

# Or, with a default
>>> value = n.get('key', 'default')

>>> for prop in n: do_something(prop)
>>> for prop, value in n.iteritems(): do_someting(prop,value) # loop through node properties

>>>more_props = { "name" : "Jack", "occupation" : "Pilot" }
>>>n1.update(more_props)
>>>n2.update(name="Sarah", occupation="Astronaut")


>>> n.id # Node id


Create relationship::

>>> n1.Knows(n2, since="A long time ago")

# Or
>>> n1.relationships("Likes")(n2, how_much="A lot") # Usefull when the name of
# relationship is stored in a variable.
# This syntax may change though... seems obscure?


The creation returns a Relationship object, which has properties accessible like nodes.

>>> rel = n1.Knows(n2, since=123456789)
>>> rel['since']
123456789

Additional attributes:

>>> rel.start # start node (n1)
>>> rel.end # end node (n2)

>>> rel.type
'Knows'



Others functions over 'relationships' attribute are possible. Like get all,
incoming or outgoing relationships (typed or not):

>>> rels = list(n1.relationships())


>>> rels = list(n1.relationships("Knows", "Likes").incoming)

>>> rel = n1.Knows.outgoing.single


Traversals
----------

In progress. Much like neo4j.py
See tests (neo4py/testing/graph_core.py)

>>> from neo4py.core import Direction
>>> from neo4py.traversal import Traverser, Stop, Returnable, Order

class MyTraverser(Traverser):
types = [Direction.Incoming.Knows, Direction.Undirected.Likes]
is_stop = lambda pos: pos.node == my_node #can use a python method #### LARGELY UNTESTED ####
#pos is a TraversalPosition object
is_returnable = Returnable.ALL #or a java defined ReturnableEvaluator/StopEvaluator
# (these are faster)
order = Order.DEPTH_FIRST


Indices
-------

See tests (neo4py/testing/graph_core.py)

>>> node_idx = gdb.node_indices.create("My node index", fulltext=True) #create an new fulltext index
#Will fail index with name already exists
>>> node_idx = gdb.node_indices["My node index"] #retrieve already created index

>>> "That index" in gdb.node_indices #test if index exists
False
>>> "My node index" in gdb.node_indices
True

>>> rel_idx = gdb.rel_indices.create("Relationship index") # works the same, but for relationships

>>> node_idx['name', "Jack"] = n1
>>> node_idx['name', "Jack"] = n500 # two nodes indexed under 'name' => "Jack"

>>>nodes = list(node_idx['name', 'Jack']) # Returns iterator over both nodes (exact matching using this syntax)

>>>nodes = list(node_idx.simple_query('name', 'jack') # fulltext query by single key/value
>>>nodes = list(node_idx.query('name:jack')) # Run lucene query (supports multiple keys)

Relationship indices same, but with a couple extra options (See Neo4j Docs):
>>> rels = list(rel_idx.simple_query('key', 'value', start_node=n1) #limit query, for efficiency (can also be end_node)
>>> rels = list(rel_idx.query('key:value', end_node=some_other_node)


Models, Django support, QuerySets, Aggregates
------

In Progress

Project details


Release history Release notifications | RSS feed

This version

0.1

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

neo4py-0.1.tar.gz (27.9 kB view hashes)

Uploaded source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page