Hello, I really like the look of neo4j and would like to use it in a project I'm working on http://pppeoplepppowered.blogspot.com/ .
I'm new to graphs and how to work with them, it's all new, but really drawn to them having banged my head on SQL schemas for years (and years). My problem with working with python neo4j is that there aren't enough simple (enough) examples. This is sort of thing is great ... http://blog.neo4j.org/2010/03/modeling-categories-in-graph-database.html ... but it doesn't explain a few things and goes wrong in places. For example, from the example, if I try to execute... computers_node = graphdb.node(Name="Computers") ... I get... jpype._jexception.RuntimeExceptionPyRaisable: org.neo4j.graphdb.NotInTransactionException: No transaction found for current thread So I need to add... with db.transaction: computers_node = graphdb.node(Name="Computers") ... which raises the issue of transactions and database connections. I'm unsure when to use transactions and how to use connections. Either way, I regularly seem to bump into a... jpype._jexception.RuntimeExceptionPyRaisable: org.neo4j.kernel.impl.transaction.TransactionFailureException: Could not create data source [nioneodb], see nested exception for cause of error Because I like to use the interpreter and learn what objects can do, and later create .py files and import them. It's not clear if I can have more than one db connection open at once, or I should open and shutdown the database everytime... or is it better to have one database connection hanging around in a file somewhere? At the moment I'm trying to create a script that, takes a csv file of people, adds them, then tries to get the data out somehow, like this... >> import stuff.neo_utils as neo # see below >> neo.import_people() #import a csv 7051 #the id of the root_person >> neo.people(7051) #get the people out via the root_person #nothing! >>neo.people(8224) # the id of the last_person <Node id=7051> My question is this... am I doing it all wrong? Could someone create a very simple example that say, populates a graph, gets data out, manipulates that data and then searches that data (say for an attribute, or to see if it exists etc) in a single python file? So that I can begin to build up my understanding, thanks for listening, tom #!/usr/bin/env python import sys, random, csv from time import sleep from random import randint import neo4j class Person(neo4j.Traversal): types = [ neo4j.Outgoing.is_a ] order = neo4j.BREADTH_FIRST stop = neo4j.STOP_AT_END_OF_GRAPH returnable = neo4j.RETURN_ALL_BUT_START_NODE def people(person_root_id ): try:graphdb.shutdown() except:pass graphdb = neo4j.GraphDatabase( "neo_db" ) with graphdb.transaction: person_root = graphdb.node[person_root_id] for person_node in Person(person_root): try: print "%s %s (@depth=%s)" % ( person_node['family_name'], person_node['email'],person_node.depth) except: print person_node graphdb.shutdown( ) # The data is like this... #tas...@york.ac.uk Staff Mr T Smith |Computing Service: | |Vanbrugh College V/C/011| |+44 1904 433847| https://www.york.ac.uk/directory/user.yrk/searchdetail.cfm?scope=staff&ref=M95%27%22%3DYBD8%5B%3ANEJ%27S%27I%2AX%20%20F%2D6Y2%3D%20SR%21A%409%2C%40E2%3D%205%2EFMOM6A%3A%3EWIHV4T%5D%5E%3B%0A%2B4%2D%2A%3EG%2D%2F6EUS%22BI0%20%0A&referrer=searchResults def import_people(name="Untitled", file='/Users/tomsmith/pppeoplepppowered/staff/staff.csv', ): 'load a lot of people into the database, connecting each to a root "Person" object by a "is_a" relationship, spurious I know ' graphdb = neo4j.GraphDatabase( "neo_db" ) with graphdb.transaction: person_root = graphdb.node(name="Person") # create a root node of sorts person_root_id = person_root.id csvReader = csv.reader(open(file), delimiter=' ', quotechar='|') for row in csvReader: email = row[0] kind = row[1] title = row[2] given_name = row[3] family_name = row[4] department = row[5] org_path = row[6] full_address = row[7] telephone = row[8] src = row[9] url = row[10] external_url = row[11] person = graphdb.node(email=email,title=title, given_name=given_name,family_name=family_name, telephone=telephone,department=department, org_path=org_path,src=src, url=url, external_url=external_url) person.is_a( person_root ) print person, "created and linked" print "done importing!" graphdb.shutdown( ) return person_root_id _______________________________________________ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
