dsProject/dsRag/Neo4j/N2_KG_FromMysql.py

import json
import pymysql
from py2neo import Graph
from Config import Config

# 连接MySQL数据库
def get_mysql_connection():
    return pymysql.connect(
        host=Config.MYSQL_HOST,
        port=Config.MYSQL_PORT,
        user=Config.MYSQL_USER,
        password=Config.MYSQL_PASSWORD,
        database=Config.MYSQL_DB_NAME,
        charset='utf8mb4'
    )

# 从MySQL获取知识点数据
def fetch_knowledge_points():
    connection = get_mysql_connection()
    try:
        with connection.cursor() as cursor:
            sql = "SELECT id, title, parent_id, is_leaf, prerequisite, related FROM knowledge_points"
            cursor.execute(sql)
            return cursor.fetchall()
    finally:
        connection.close()

# 生成Cypher语句
def generate_cypher(knowledge_points):
    cypher = []
    
    # 创建所有知识点节点
    for point in knowledge_points:
        node_id = point[0]
        title = point[1].replace("'", "''")
        is_leaf = point[3]
        
        cypher.append(
            f"MERGE (n:KnowledgePoint {{id: '{node_id}'}}) "
            f"SET n.name = '{title}', n.is_leaf = {is_leaf};"
        )
    
    # 创建父子关系
    for point in knowledge_points:
        node_id = point[0]
        parent_id = point[2]
        
        if parent_id:
            cypher.append(
                f"MATCH (parent:KnowledgePoint {{id: '{parent_id}'}}), "
                f"(child:KnowledgePoint {{id: '{node_id}'}}) "
                f"MERGE (parent)-[:HAS_SUB_POINT]->(child);"
            )
    
    # 处理先修知识关系
    for point in knowledge_points:
        node_id = point[0]
        prerequisite = json.loads(point[4] if point[4] else '[]')
        
        for req in prerequisite:
            req_id = req['id']
            cypher.append(
                f"MATCH (a:KnowledgePoint {{id: '{node_id}'}}), "
                f"(b:KnowledgePoint {{id: '{req_id}'}}) "
                f"MERGE (a)-[:PREREQUISITE]->(b);"
            )
    
    # 处理相关知识关系
    for point in knowledge_points:
        node_id = point[0]
        related = json.loads(point[5] if point[5] else '[]')
        
        for rel in related:
            rel_id = rel['id']
            cypher.append(
                f"MATCH (a:KnowledgePoint {{id: '{node_id}'}}), "
                f"(b:KnowledgePoint {{id: '{rel_id}'}}) "
                f"MERGE (a)-[:RELATED]->(b);"
            )
    
    return '\n'.join(cypher)

# 主函数
def main():
    # 连接Neo4j
    graph = Graph(Config.NEO4J_URI, auth=Config.NEO4J_AUTH)
    
    # 清空现有数据
    graph.run("MATCH (n) DETACH DELETE n")
    
    # 从MySQL获取数据
    knowledge_points = fetch_knowledge_points()
    
    # 生成Cypher语句列表
    cypher_statements = generate_cypher(knowledge_points)
    
    # 逐条执行Cypher语句
    for statement in cypher_statements.split('\n'):
        if statement.strip():  # 跳过空行
            graph.run(statement)
    
    print("知识图谱数据导入成功！")

if __name__ == '__main__':
    main()