知识图谱-知识存储-py2neo使用

    使用py2neo实现python对Neo4j的操作，首先是搭建环境，选用合适的版本对实验的成功至关重要。我选用的版本是Neo4j—3.0.7、py2neo—3.1.2、python2.7。需要注意的是如果使用默认的pip install py2neo则在进行create node时会出现报错问题，因此需选择合适的版本。

       程序代码及注释如下

# -*- coding: utf-8 -*-

from py2neo import Graph, Node, Relationship, NodeSelector

graph = Graph("http://localhost:7474", username="neo4j", password='password')
graph.delete_all()

'''
    1 —— 创建node，函数第一个参数是节点类型，第二个参数是value值
'''
a = Node('PersonTest', name='张三')
b = Node('PersonTest', name='李四')
r = Relationship(a, 'KNOWNS', b)
s = a | b | r
graph.create(s)

'''
    2　——　Node查询
'''
# 用CQL进行查询，返回的结果是list
data1 = graph.data('MATCH(p:PersonTest) return p')
print "data1 = ", data1, type(data1)
print
# 用find_one()方法进行node查找，返回的是查找node的第一个node
data2 = graph.find_one(label='PersonTest', property_key='name', property_value="李四")
print "data2 = ", data2, type(data2)
print
# 用find()方法进行node查找
data3 = graph.find(label='PersonTest')
for data in data3:
    print "data3 = ", data
print
'''
    3　——　Relationship查询
'''
relationship = graph.match_one(rel_type='KNOWNS')
print relationship, type(relationship)
print

'''
    4 —— 更新Node的某个属性值，若node没有该属性，则新增该属性
'''
node1 = graph.find_one(label='PersonTest', property_key='name', property_value="张三")
node1['age'] = 21
graph.push(node1)
data4 = graph.find(label='PersonTest')
for data in data4:
    print "data4 = ", data
print

node1['age'] = 99
graph.push(node1)
data5 = graph.find(label='PersonTest')
for data in data5:
    print "data5 = ", data
print

'''
    5 —— 删除某node，在删除node之前需要先删除relationship
'''
node = graph.find_one(label='PersonTest', property_key='name', property_value="李四")
relationship = graph.match_one(rel_type='KNOWNS')
graph.delete(relationship)
graph.delete(node)
data6 = graph.find(label='PersonTest')
for data in data6:
    print "data6 = ", data

'''
    6 —— 多条件查询
'''
a = Node('PersonTest', name='张三', age=21, location='广州')
b = Node('PersonTest', name='李四', age=22, location='上海')
c = Node('PersonTest', name='王五', age=21, location='北京')
r1 = Relationship(a, 'KNOWS', b)
r2 = Relationship(b, 'KNOWS', c)
s = a | b | c | r1 | r2
graph.create(s)
data7 = graph.find(label='PersonTest')
for data in data7:
    print "data7 = ", data
print

# 单条件查询，返回的是多个结果
selector = NodeSelector(graph)
persons = selector.select('PersonTest', age=21)
print("data8 = ", list(persons))
print

# 多条件查询
selector = NodeSelector(graph)
persons = selector.select('PersonTest', age=21, location='广州')
print("data9 = ", list(persons))
print

# orderby进行更复杂的查询
selector = NodeSelector(graph)
persons = selector.select('PersonTest').order_by('_.age')
for data in persons:
    print "data10 = ", data
print

改代码运行结果如下

data1 =  [{u'p': (`张三`:PersonTest {name:"张三"})}, {u'p': (`李四`:PersonTest {name:"李四"})}] <type 'list'>

data2 =  (`李四`:PersonTest {name:"李四"}) <class 'py2neo.types.Node'>

data3 =  (`张三`:PersonTest {name:"张三"})
data3 =  (`李四`:PersonTest {name:"李四"})

(`张三`)-[:KNOWNS]->(`李四`) <class 'py2neo.types.Relationship'>

data4 =  (`张三`:PersonTest {age:21,name:"张三"})
data4 =  (`李四`:PersonTest {name:"李四"})

data5 =  (`张三`:PersonTest {age:99,name:"张三"})
data5 =  (`李四`:PersonTest {name:"李四"})

data7 =  (`张三`:PersonTest {age:21,location:"广州",name:"张三"})
data7 =  (`李四`:PersonTest {age:22,location:"上海",name:"李四"})
data7 =  (`王五`:PersonTest {age:21,location:"北京",name:"王五"})

('data8 = ', [(`张三`:PersonTest {age:21,location:"广州",name:"张三"}), (`王五`:PersonTest {age:21,location:"北京",name:"王五"})])

('data9 = ', [(`张三`:PersonTest {age:21,location:"广州",name:"张三"})])

data10 =  (`张三`:PersonTest {age:21,location:"广州",name:"张三"})
data10 =  (`王五`:PersonTest {age:21,location:"北京",name:"王五"})
data10 =  (`李四`:PersonTest {age:22,location:"上海",name:"李四"})