Python连接Neo4j数据库的操作指南

pip install py2neo

from py2neo import Graph

# 连接到本地的 Neo4j 数据库
graph = Graph("bolt://localhost:7687", auth=("neo4j", "your_password"))

# 检查连接是否成功
print(graph.run("RETURN 'Hello, Neo4j!'").data())

from py2neo import Node

# 创建节点：Person 节点
person = Node("Person", name="John", age=30)

# 将节点保存到图数据库
graph.create(person)

# 查看节点是否创建成功
print(person)

# 创建两个节点
john = Node("Person", name="John", age=30)
jane = Node("Person", name="Jane", age=28)

# 创建关系：John -> Jane, 关系类型为 "FRIEND"
john_knows_jane = john.create_relationship_to(jane, "FRIEND")

# 保存节点和关系
graph.create(john)
graph.create(jane)

# 查看关系
print(john_knows_jane)

# 使用 Cypher 查询获取所有 Person 节点
query = "MATCH (p:Person) RETURN p.name, p.age"
result = graph.run(query)

# 输出查询结果
for record in result:
    print(record["p.name"], record["p.age"])

# 查询所有与 John 相关的 FRIEND 关系
query = "MATCH (p:Person)-[:FRIEND]->(f:Person) WHERE p.name = 'John' RETURN f.name"
result = graph.run(query)

# 输出查询结果
for record in result:
    print(record["f.name"])

# 查询所有的节点和它们的关系
query = "MATCH (a)-[r]->(b) RETURN a.name, type(r), b.name"
result = graph.run(query)

# 输出查询结果
for record in result:
    print(f"{record['a.name']} is {record['type(r)']} {record['b.name']}")

# 查找节点并更新其属性
query = "MATCH (p:Person {name: 'John'}) SET p.age = 31"
graph.run(query)

# 删除一个节点
query = "MATCH (p:Person {name: 'John'}) DELETE p"
graph.run(query)

# 删除节点之间的关系
query = "MATCH (a)-[r:FRIEND]->(b) DELETE r"
graph.run(query)

from py2neo import Transaction

# 使用事务批量插入数据
tx = graph.begin()

# 创建多个节点和关系
for i in range(1, 6):
    person = Node("Person", name=f"Person_{i}", age=20 + i)
    tx.create(person)
    
    if i > 1:
        prev_person = graph.nodes.match("Person", name=f"Person_{i-1}").first()
        person.create_relationship_to(prev_person, "KNOWS")

# 提交事务
tx.commit()

try:
    # 尝试连接 Neo4j 数据库
    graph = Graph("bolt://localhost:7687", auth=("neo4j", "wrong_password"))
    # 执行查询
    result = graph.run("MATCH (p:Person) RETURN p.name")
    for record in result:
        print(record["p.name"])
except Exception as e:
    print(f"发生错误: {e}")