知识图谱环境搭建——安装Neo4j
一、下载Neo4j社区版4.2.2
https://neo4j.com/download-center/#community
二、下载JDK 11
https://www.oracle.com/java/technologies/javase-jdk11-downloads.html
三、运行Neo4j
打开终端，进入Neo4j目录
cd /Users/zmz/Downloads/neo4j-community-4.2.2
执行命令：
bin/neo4j start
打开浏览器，进入网址
http://127.0.0.1:7474/browser/
默认用户名密码均为neo4j，第一次登陆修改密码后即可进入
四、使用Neo4j
1、创建一个人物节点：在最上方的命令处输入
CREATE (n:Person {name:'John'}) RETURN n
然后创建更多人物节点
CREATE (n:Person {name:'Sally'}) RETURN n
CREATE (n:Person {name:'Steve'}) RETURN n
CREATE (n:Person {name:'Mike'}) RETURN n
CREATE (n:Person {name:'Liz'}) RETURN n
CREATE (n:Person {name:'Shawn'}) RETURN n
2、创建地区节点
CREATE (n:Location {city:'Miami', state:'FL'})
CREATE (n:Location {city:'Boston', state:'MA'})
CREATE (n:Location {city:'Lynn', state:'MA'})
CREATE (n:Location {city:'Portland', state:'ME'})
CREATE (n:Location {city:'San Francisco', state:'CA'})
可以看到有人节点，有地区节点
3、让我们创建一个朋友关系
MATCH (a:Person {name:'Liz'}),
(b:Person {name:'Mike'})
MERGE (a)-[:FRIENDS]->(b)
关系增加属性
MATCH (a:Person {name:'Shawn'}),
(b:Person {name:'Sally'})
MERGE (a)-[:FRIENDS {since:2001}]->(b)
增加更多的朋友关系
MATCH (a:Person {name:'Shawn'}), (b:Person {name:'John'}) MERGE (a)-[:FRIENDS {since:2012}]->(b)
MATCH (a:Person {name:'Mike'}), (b:Person {name:'Shawn'}) MERGE (a)-[:FRIENDS {since:2006}]->(b)
MATCH (a:Person {name:'Sally'}), (b:Person {name:'Steve'}) MERGE (a)-[:FRIENDS {since:2006}]->(b)
MATCH (a:Person {name:'Liz'}), (b:Person {name:'John'}) MERGE (a)-[:MARRIED {since:1998}]->(b)
这样，图谱就建立好了
4、建立不同类型节点之间的关系：人物和地点的关系
MATCH (a:Person {name:'John'}), (b:Location {city:'Boston'}) MERGE (a)-[:BORN_IN {year:1978}]->(b)
MATCH (a:Person {name:'Liz'}), (b:Location {city:'Boston'}) MERGE (a)-[:BORN_IN {year:1981}]->(b)
MATCH (a:Person {name:'Mike'}), (b:Location {city:'San Francisco'}) MERGE (a)-[:BORN_IN {year:1960}]->(b)
MATCH (a:Person {name:'Shawn'}), (b:Location {city:'Miami'}) MERGE (a)-[:BORN_IN {year:1960}]->(b)
MATCH (a:Person {name:'Steve'}), (b:Location {city:'Lynn'}) MERGE (a)-[:BORN_IN {year:1970}]->(b)
也可在创建节点时就建好关系
CREATE (a:Person {name:'Todd'})-[r:FRIENDS]->(b:Person {name:'Carlos'})
五、图数据库查询
1、查询下所有在Boston出生的人物
MATCH (a:Person)-[:BORN_IN]->(b:Location {city:'Boston'}) RETURN a,b
2、查询所有对外有关系的节点
MATCH (a)--() RETURN a
六、删除和修改
1、增加/修改节点的属性
MATCH (a:Person {name:'Liz'}) SET a.age=34
MATCH (a:Person {name:'Shawn'}) SET a.age=32
MATCH (a:Person {name:'John'}) SET a.age=44
MATCH (a:Person {name:'Mike'}) SET a.age=25
2、删除节点的属性
MATCH (a:Person {name:'Mike'}) SET a.test='test'
MATCH (a:Person {name:'Mike'}) REMOVE a.test
七、通过python操作Neo4j
1、 neo4j模块：执行CQL ( cypher ) 语句
# step 1：导入 Neo4j 驱动包
from neo4j import GraphDatabase
# step 2：连接 Neo4j 图数据库
driver = GraphDatabase.driver("bolt://localhost:7687", auth=("neo4j", "password"))
# 添加 关系 函数
def add_friend(tx, name, friend_name):
tx.run("MERGE (a:Person {name: $name}) "
"MERGE (a)-[:KNOWS]->(friend:Person {name: $friend_name})",
name=name, friend_name=friend_name)
# 定义 关系函数
def print_friends(tx, name):
for record in tx.run("MATCH (a:Person)-[:KNOWS]->(friend) WHERE a.name = $name "
"RETURN friend.name ORDER BY friend.name", name=name):
print(record["friend.name"])
# step 3：运行
with driver.session() as session:
session.write_transaction(add_friend, "Arthur", "Guinevere")
session.write_transaction(add_friend, "Arthur", "Lancelot")
session.write_transaction(add_friend, "Arthur", "Merlin")
session.read_transaction(print_friends, "Arthur")
或者：
neo4j.GraphDatabase.driver(xxxx).session().write_transaction(函数(含tx.run(CQL语句)))
或者：
neo4j.GraphDatabase.driver(xxxx).session().begin_transaction.run(CQL语句)
2、py2neo模块：通过操作python变量，达到操作neo4j的目的
# step 1：导包
from py2neo import Graph, Node, Relationship
# step 2：构建图
g = Graph()
# step 3：创建节点
tx = g.begin()
a = Node("Person", name="Alice")
tx.create(a)
b = Node("Person", name="Bob")
# step 4：创建边
ab = Relationship(a, "KNOWS", b)
# step 5：运行
tx.create(ab)
tx.commit()
参考资料
干货 | 从零到一学习知识图谱的技术与应用
手把手教你快速入门知识图谱 - Neo4J教程
python操作图数据库neo4j的两种方式
Neo4j之导入数据
schema 介绍
知识图谱Schema
美团大脑：知识图谱的建模方法及其应用
肖仰华.知识图谱:概念与技术.北京:电子工业出版社,2020.2－39.