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知識圖譜-知識儲存-py2neo使用

    使用py2neo實現python對Neo4j的操作,首先是搭建環境,選用合適的版本對實驗的成功至關重要。我選用的版本是Neo4j—3.0.7、py2neo—3.1.2、python2.7。需要注意的是如果使用預設的pip install py2neo則在進行create node時會出現報錯問題,因此需選擇合適的版本。

       程式程式碼及註釋如下

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

from py2neo import Graph, Node, Relationship, NodeSelector

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

'''
    1 —— 建立node,函式第一個引數是節點型別,第二個引數是value值
'''
a = Node('PersonTest', name='張三')
b = Node('PersonTest', name='李四')
r = Relationship(a, 'KNOWNS', b)
s = a | b | r
graph.create(s)

'''
    2 —— Node查詢
'''
# 用CQL進行查詢,返回的結果是list
data1 = graph.data('MATCH(p:PersonTest) return p')
print "data1 = ", data1, type(data1)
print
# 用find_one()方法進行node查詢,返回的是查詢node的第一個node
data2 = graph.find_one(label='PersonTest', property_key='name', property_value="李四")
print "data2 = ", data2, type(data2)
print
# 用find()方法進行node查詢
data3 = graph.find(label='PersonTest')
for data in data3:
    print "data3 = ", data
print
'''
    3 —— Relationship查詢
'''
relationship = graph.match_one(rel_type='KNOWNS')
print relationship, type(relationship)
print

'''
    4 —— 更新Node的某個屬性值,若node沒有該屬性,則新增該屬性
'''
node1 = graph.find_one(label='PersonTest', property_key='name', property_value="張三")
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 —— 刪除某node,在刪除node之前需要先刪除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 —— 多條件查詢
'''
a = Node('PersonTest', name='張三', age=21, location='廣州')
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

# 單條件查詢,返回的是多個結果
selector = NodeSelector(graph)
persons = selector.select('PersonTest', age=21)
print("data8 = ", list(persons))
print

# 多條件查詢
selector = NodeSelector(graph)
persons = selector.select('PersonTest', age=21, location='廣州')
print("data9 = ", list(persons))
print

# orderby進行更復雜的查詢
selector = NodeSelector(graph)
persons = selector.select('PersonTest').order_by('_.age')
for data in persons:
    print "data10 = ", data
print

改程式碼執行結果如下

data1 =  [{u'p': (`張三`:PersonTest {name:"張三"})}, {u'p': (`李四`:PersonTest {name:"李四"})}] <type 'list'>

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

data3 =  (`張三`:PersonTest {name:"張三"})
data3 =  (`李四`:PersonTest {name:"李四"})

(`張三`)-[:KNOWNS]->(`李四`) <class 'py2neo.types.Relationship'>

data4 =  (`張三`:PersonTest {age:21,name:"張三"})
data4 =  (`李四`:PersonTest {name:"李四"})

data5 =  (`張三`:PersonTest {age:99,name:"張三"})
data5 =  (`李四`:PersonTest {name:"李四"})

data7 =  (`張三`:PersonTest {age:21,location:"廣州",name:"張三"})
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 = ', [(`張三`:PersonTest {age:21,location:"廣州",name:"張三"}), (`王五`:PersonTest {age:21,location:"北京",name:"王五"})])

('data9 = ', [(`張三`:PersonTest {age:21,location:"廣州",name:"張三"})])

data10 =  (`張三`:PersonTest {age:21,location:"廣州",name:"張三"})
data10 =  (`王五`:PersonTest {age:21,location:"北京",name:"王五"})
data10 =  (`李四`:PersonTest {age:22,location:"上海",name:"李四"})