本文档将介绍在CentOS 7.3上部署图数据库Neo4j，包括使用Python访问Neo4j图数据库。
步骤一：安装JDK(略)
步骤二：安装Python 2.7版本
[root@openstack-node1 tmp]# python -V Python 2.7.5
步骤三：安装neo4j
[root@openstack-node1 tmp]# cd /tmp [root@openstack-node1 tmp]# wget http://debian.neo4j.org/neotechnology.gpg.key [root@openstack-node1 tmp]# rpm --import neotechnology.gpg.key [root@openstack-node1 tmp]# cat <<EOF > /etc/yum.repos.d/neo4j.repo > [neo4j] > name=Neo4j Yum Repo > baseurl=http://yum.neo4j.org/stable > enabled=1 > gpgcheck=1 > EOF [root@openstack-node1 tmp]# yum install neo4j -y
步骤三：安装Python的接口驱动去访问Neo4j
[root@openstack-node1 tmp]# yum -y install epel-release [root@openstack-node1 tmp]# yum -y install python-pip [root@openstack-node1 tmp]# pip install neo4j-driver [root@openstack-node1 tmp]# pip install --upgrade pip
步骤四：启动Neo4j
[root@openstack-node1 tmp]# neo4j --help
Usage: neo4j { console | start | stop |restart | status | version }
[root@openstack-node1 tmp]# neo4j console
Active database: graph.db
Directories in use:
home: /var/lib/neo4j
config: /etc/neo4j
logs: /var/log/neo4j
plugins: /var/lib/neo4j/plugins
import: /var/lib/neo4j/import
data: /var/lib/neo4j/data
certificates: /var/lib/neo4j/certificates
run: /var/run/neo4j
Starting Neo4j.
……
安装好以后，在控制台启动Neo4j，然后打开浏览器访问http://192.168.1.11:7474/ ，就可以查看Neo4j服务了。
登录图数据库的时候使用默认的用户名和密码(neo4j)连接，连接成功后需要修改neo4j的默认密码。
步骤五：运行Python测试用例
Neo4j支持一种叫做cypher的图查询语言，这里定义一个执行cypher的函数，然后调用插入一些测试数据，代码如下：
# !/usr/bin/python
# -*- coding: utf-8 -*-
"""
create_author : jiangshouzhuang
create_time : 2017-06-07
program : *_* Read and Write Neo4j *_*
"""
from neo4j.v1 import GraphDatabase
class Neo4jHandler:
"""
Handler of graph database Neo4j reading and writing.
"""
def __init__(self,driver):
"""
Get Neo4j server driver.
:param driver: driver object
A driver object holds the detail of a Neo4j database including serverURIs,credentials and other configuration,see
" http://neo4j.com/docs/api/python-driver/current/driver.html".
"""
self.driver = driver
def __repr__(self):
printer = 'o(>﹏<)o ......Neo4j old driver "{0}" carry me fly......o(^o^)o'.format(self.driver)
return printer
def listreader(self,cypher,keys):
"""
Read data from Neo4j in specified cypher.
Read and parse data straightly from cypher field result.
:param cypher: string
Valid query cypher statement.
:param keys: list
Cypher query columns to return.
:return: list
Each returned record constructs a list and stored in a big list,[[...],[...],...].
"""
with self.driver.session() as session:
with session.begin_transaction() as tx:
data = []
result = tx.run(cypher)
for record in result:
rows = []
for key in keys:
rows.append(record[key])
data.append(rows)
return data
def dictreader(self,cypher):
"""
Read data from Neo4j in specified cypher.
The function depends on constructing dict method of dict(key = value) andany error may occur if the "key" is invalid to Python.
you can choose function dictreaderopted() below to read data by hand(viathe args "keys").
:param cypher: string
Valid query cypher statement.
:return: list
Each returned record constructs a dict in "key : value" pairsand stored in a big list,[{...},{...},...].
"""
with self.driver.session() as session:
with session.begin_transaction() as tx:
data = []
for record intx.run(cypher).records():
item = {}
for args instr(record).split('>')[0].split()[1:]:
exec"item.update(dict({0}))".format(args)
data.append(item)
return data
def dictreaderopted(self,keys=None):
"""
Optimized function of dictreader().
Read and parse data straightly from cypher field result.
:param cypher: string
Valid query cypher statement.
:param keys: list,default : none(call dictreader())
Cypher query columns to return.
:return: list.
Each returned record constructs an dict in "key : value" pairsand stored in a list,...].
"""
if not keys:
return self.dictreader(cypher)
else:
with self.driver.session() as session:
with session.begin_transaction()as tx:
data = []
result =tx.run(cypher)
for record in result:
item = {}
for key in keys:
item.update({key :record[key]})
data.append(item)
return data
def cypherexecuter(self,cypher):
"""
Execute manipulation into Neo4j in specified cypher.
:param cypher: string
Valid handle cypher statement.
:return: none.
"""
with self.driver.session() as session:
with session.begin_transaction() as tx:
tx.run(cypher)
session.close()
# self test
if __name__ == "__main__":
uri = "bolt://192.168.1.11:7687"
driver = GraphDatabase.driver(uri,auth=("neo4j","zhangyun"))
MyNH = Neo4jHandler(driver)
print(MyNH)
cypher_exec = """
CREATE (Neo:Crew{name:'Neo'}),(Morpheus:Crew{name: 'Morpheus'}),(Trinity:Crew {name:'Trinity'}),(Cypher:Crew:Matrix{name: 'Cypher'}),(Smith:Matrix {name:'Agent Smith'}),(Architect:Matrix{name:'The Architect'}),(Neo)-[:KNowS]->(Morpheus),(Neo)-[:lovES]->(Trinity),(Morpheus)-[:KNowS]->(Trinity),(Morpheus)-[:KNowS]->(Cypher),(Cypher)-[:KNowS]->(Smith),(Smith)-[:CODED_BY]->(Architect)
""" # "example cypher statement fromhttp://console.neo4j.org/"
cypher_read = """
MATCH (a)-[:KNowS|lovES]-> (b:Crew {name: 'Trinity'})
RETURN a.name AS l,b.nameAS r
"""
MyNH.cypherexecuter(cypher_exec)
print(MyNH.listreader(cypher_read,['l','r']))
print(MyNH.dictreader(cypher_read))
print(MyNH.dictreaderopted(cypher_read,['l']))
将上述的代码保存到本地的文件中，比如neo4j_python_example.py，然后运行：
[root@openstack-node1 neo4j]# pythonneo4j_python_example.py
o(>﹏<)o ......Neo4jold driver "<neo4j.v1.direct.DirectDriver object at0x7f87bcc6eed0>" carry me fly...... o(^o^)o
[[u'Morpheus',u'Trinity'],[u'Neo',u'Trinity']]
[{'r': u'Trinity','l': u'Morpheus'},{'r':u'Trinity','l': u'Neo'}]
[{'l': u'Morpheus'},{'l': u'Neo'}]
然后再登录Neo4j查看：