在Python中使用Neo4j数据库的教程

#!/usr/bin/env python
# -*- coding: utf-8 -*-
 
from __future__ import print_function
 
import sys
from py2neo import neo4j, node, rel
 
graph_db = neo4j.GraphDatabaseService()
 
class Person(object):
   
  _root = graph_db.get_or_create_indexed_node("reference",
     "contacts", "root")
   
  @classmethod
  def create(cls, name, *emails):
    person_node, _ = graph_db.create(node(name=name),
       rel(cls._root, "PERSON", 0))
    for email in emails:
      graph_db.create(node(email=email), rel(cls._root, "EMAIL", 0),
         rel(person_node, "EMAIL", 0))
    return Person(person_node)
   
  @classmethod
  def get_all(cls):
    return [Person(person.end_node) for person in
       cls._root.match("PERSON")]
   
  def __init__(self, node):
    self._node = node
   
  def __str__(self):
    return self.name + "\n" + "\n".join(" <{0}>"
       .format(email) for email in self.emails)
   
  @property
  def name(self):
    return self._node["name"]
   
  @property
  def emails(self):
    return [rel.end_node["email"] for rel in
       self._node.match("EMAIL")]
 
if __name__ == "__main__":
  if len(sys.argv) < 2:
    app = sys.argv[0]
    print("Usage: {0} add  
       [...]".format(app))
    print("    {0} list".format(app))
    sys.exit()
  method = sys.argv[1]
  if method == "add":
    print(Person.create(*sys.argv[2:]))
  elif method == "list":
    for person in Person.get_all():
      print(person)
  else:
print("Unknown command")

在第09行上是第一行Py2neo代码，用来创建了一个GraphDatabaseService对象。通过这个，我们就可以访问使用Neo4j server的大多数功能。可选一个URI传递到这个构造器里，尽管如果什么都没有提供，代而取之的是使用默认的本地参数。也就是说下面两行是完全相等的：

graph_db = neo4j.GraphDatabaseService()
graph_db = neo4j.GraphDatabaseService
("http://localhost:7474/db/data/")