文章目录

一、python 与neo4j 数据库交互
- 1.创建图对象
- 2.创建数据对象
- - Relationship
  - query
  - - 匹配所有节点
    - 匹配符合指定条件节点
  - Update
  - - 修改单个节点
    - 修改多个节点
    - 两个节点新加关系
  - 删除
  - - 删除关系链 delete
    - 只删除关系 separate
  - 批处理
  - - 创建多个节点
    - 删除所有的关系
二、版本问题
三、参考链接

一、python 与neo4j 数据库交互

py2neo==4.3.0

1.创建图对象

from py2neo import Graph
'''
host:服务器ip地址，默认为'localhost'
http_port:http协议——服务器监听端口，默认7474
https_port:https协议——服务器监听端口，默认7473
user:登录用户名，默认'neo4j'
password:登录密码，无默认值，故若数据库其他参数都为默认值，则可直接通过密码登录
'''
graph = Graph('http://localhost:7474', auth=("neo4j", "123456"))

2.创建数据对象

Relationship

from py2neo import Graph, Node, Relationshipg = Graph('http://localhost:7474', username='neo4j', password='123456')
a = Node('Person', name='Alice')
b = Node('Person', name='Bob')
ab = Relationship(a, 'KNOWS', b)
g.create(ab)

query

# 新版
from py2neo import Graph, Node, Relationship, Subgraphg = Graph('http://localhost:7474', username='neo4j', password='123456')tx = g.begin()
jiazhen = Node("Person", name="陈家珍", age=66)
fugui = Node("Person", name='徐福贵', age=67)
youqian = Node("Person", name="徐有钱")
renxing = Node("Person", name="徐任性")cat = Node("Person", name='cat')
dog = Node("Person", name='dog')wife = Relationship(fugui, "WIFE", jiazhen)
brother_1 = Relationship(fugui, "BROTHER", youqian)
brother_2 = Relationship(fugui, "BROTHER", renxing)
hus = Relationship(jiazhen, 'HUS', fugui)
know = Relationship(cat, 'KNOWS', dog)relation_list = Subgraph(relationships=[wife, brother_2, brother_1, hus, know])tx.create(relation_list)
tx.commit()

匹配所有节点

from py2neo import Graph, Node, Relationshipg = Graph('http://localhost:7474', auth=("neo4j", "123456"))nodes = g.nodes.match()for node in nodes:print(node)
print(node.items())
print(node.labels)

匹配符合指定条件节点

from py2neo import Graph, Node, Relationship, NodeMatcherg = Graph('http://localhost:7474', auth=("neo4j", "123456"))# 用来查找节点的对象
matcher = NodeMatcher(g)# first 返回第一个符合条件的节点
# node1 = matcher.match('Person', name='徐有钱').first()
node1 = matcher.match('Person').where("_.name='徐有钱'").first()
print(node1)# all 返回所有符合条件的节点
nodes = matcher.match('Person')for node in nodes:print('姓名：%s \t 年龄：%s '% (node['name'], node['age']))nodes = matcher.match('Person').where("_.age=66")
print('*' * 25 + '年龄66的节点' + '*' * 25)
for node in nodes:print('姓名：%s \t 年龄：%s ' % (node['name'], node['age']))# 模糊匹配 要用Cypher
nodes = matcher.match("Person").where("_.name =~ '徐.*'")print('*' * 25 + '姓徐的节点' + '*' * 25)
for node in nodes:print('姓名：%s \t 年龄：%s ' % (node['name'], node['age']))

Update

py2neo==2020.1.0

本来想继续使用py2neo==4.3.0版本，无奈总是报错，针对该错误的情况的代码修改方式较少，更多的推荐是更改py2neo版本。

修改单个节点

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraphg = Graph('http://localhost:7474', auth=("neo4j", "123456"))from py2neo import Graph, NodeMatchertx = g.begin()
# 找到你要找的Nodes
matcher = NodeMatcher(g)# 修改单个节点
init_node = matcher.match("Person").where('_.name="徐福贵"')
new_node = init_node.first()
new_node['name'] = "福贵"
sub = Subgraph(nodes=[new_node])
tx.push(sub)
tx.commit()

修改多个节点

# 修改多个节点
from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraphg = Graph('http://localhost:7474', auth=("neo4j", "123456"))from py2neo import Graph, NodeMatchertx = g.begin()
# 找到你要找的Nodes
matcher = NodeMatcher(g)init_node = matcher.match("Person")
new_nodes = []
for node in init_node.all():node['name'] = '⭐'+node['name']new_nodes.append(node)sub = Subgraph(nodes=new_nodes)
tx.push(sub)
tx.commit()

两个节点新加关系

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraphg = Graph('http://localhost:7474', auth=("neo4j", "123456"))matcher = NodeMatcher(g)fugui = matcher.match('Person', name='⭐福贵').first()
youqian = matcher.match('Person', name='⭐徐有钱').first()relation = Relationship(fugui, 'Brother', youqian)g.create(relation)

删除

删除关系链 delete

节点也会被删除

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraph, RelationshipMatcherg = Graph('http://localhost:7474', auth=("neo4j", "123456"))matcher = NodeMatcher(g)
r_matcher = RelationshipMatcher(g)
a = matcher.match('Person', name='⭐Alice').first()
b = matcher.match('Person', name='⭐Bob').first()relation = r_matcher.match(nodes=[a, b]).first()    #也可以是none,表示任意节点。注意前后顺序
# nodes=[None,b] 表示所有以b为终点的关系
# nodes=[a,None] 表示所有以a为起点的关系
# nodes=[None,None] 表示所有节点的关系
print(relation)
g.delete(relation)

只删除关系 separate

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraph, RelationshipMatcherg = Graph('http://localhost:7474', auth=("neo4j", "123456"))matcher = NodeMatcher(g)
r_matcher = RelationshipMatcher(g)
cat = matcher.match('Person', name='⭐cat').first()
dog = matcher.match('Person', name='⭐dog').first()relation = r_matcher.match(nodes=[cat, dog]).first()
print(relation)
g.separate(relation)

批处理

创建多个节点

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraph, RelationshipMatcherg = Graph('http://localhost:7474', auth=("neo4j", "123456"))tx = g.begin()
node_list = [Node("Num", name=str(i)) for i in range(4)]node_list = Subgraph(nodes=node_list)tx.create(node_list)
tx.commit()

删除所有的关系

from py2neo import Graph, Node, Relationship, NodeMatcher, Subgraph, RelationshipMatcherg = Graph('http://localhost:7474', auth=("neo4j", "123456"))
matcher = RelationshipMatcher(g)
tx = g.begin()
relationship_list = matcher.match().all()node_list = Subgraph(relationships=relationship_list)tx.separate(node_list)
tx.commit()

二、版本问题

Neo4j版本4.2.1，Python版本3.6 的条件下 py2neo4.3.0版本无法使用

NodeMatcher(graph).match().all()

py2neo4.0.0版本可使用NodeMatcher(graph).match().all()，但无法与当前版本的Neo4j建立连接

py2neo4.3.0版本可以使用

NodeMatcher(graph).match().first()

py2neo4.3.0版本无法使用

node1 = matcher.match('Person', name='徐有钱').first()