图数据库neo4j-Echarts可视化

Neo4j Flask Echarts

安装 Neo4j

Neo4j依赖Java环境，所以需要先安装JDK， JDK下载地址如下：

• https://www.oracle.com/java/technologies/downloads/
  最新版的Neo4j需要java11版本以上，所以按需求安装对应的版本即可。

Neo4j下载地址如下：

• https://neo4j.com/download-center/#community

社区版是免费的，所以选择社区版安装最新版即可。
另：Neo4j 插件 apoc 安装地址如下（插件根据需求安装）：

• https://github.com/neo4j-contrib/neo4j-apoc-procedures/releases

插件这里有个小坑，就是版本之间的依赖，如果Neo4j下载的是最新版，插件也最好选择最新版进行安装。
下载完后直接放在 neo4j-community-4.4.4/plugins 目录下，并且需要在配置文件里进行设置。

启动 Neo4j

如果是桌面端直接运行程序即可，如果是server端配置好环境后运行 neo4j start 即可启动，停止运行命令：neo4j stop
启动后可以在浏览器输入 http://localhost:7474/ 进入数据库，初始用户名和密码均是：neo4j，第一次进入需要修改密码，自行修改即可。
另外neo4j自带的数据库为 system 和 neo4j。如果想创建一个新的数据库需要在配置文件里修改，配置文件地址为：

• neo4j-community-4.4.4/conf/neo4j.conf

修改默认数据库
#The name of the default database
#dbms.default_database=neo4j
dbms.default_database=test

修改插件配置
# A comma separated list of procedures and user defined functions that are allowed
# full access to the database through unsupported/insecure internal APIs.
#dbms.security.procedures.unrestricted=my.extensions.example,my.procedures.*
dbms.security.procedures.unrestricted=apoc.*

修改免密登陆（测试需求）
# Whether requests to Neo4j are authenticated.
# To disable authentication, uncomment this line
dbms.security.auth_enabled=false

其它配置有需求再进行修改。

Neo4j 节点和关系创建

• 参考教程：https://www.w3cschool.cn/neo4j/
• python方法

## pip install py2neo 
from py2neo import *

# 连接neo4j数据库，输入地址、用户名、密码
graph = Graph("bolt://localhost:7687", auth=('neo4j','neo4j'))
graph.delete_all() #清除neo4j中原有的结点等所有信息

# 随机生成100个节点
N = 100
node_ls = []
for i in range(N):
	random_name = "P"+str(round(random.random()*N*2))
	random_age = round(random.random()*15)
	node = Node("Person", name=random_name, age=random_age)
	node_ls.append(node)

subgraph = Subgraph(node_ls, [])    ## [] 代表关系为空
tx = graph.begin() 
tx.create(subgraph)
graph.commit(tx)

详情可参考：https://mp.weixin.qq.com/s/1DnMHOx6jPi0j0GhZwNPqw

Echarts可视化

neo4j本身有自己的可视化系统，比如browser、Bloom等，但是blowser面向开发者，Bloom又是收费的，所以只能自己动手了。

## 主要就是 option的设置
var categories = [{name:"DrugName"},{name:"TargetGene"},{name:"DiseaseLabel"}];

option = {
    // color:['#5470c6', '#91cc75', '#fac858', '#ee6666', '#73c0de', '#3ba272', '#fc8452', '#9a60b4', '#ea7ccc'],
    tooltip: {
     trigger: 'item',
     triggerOn: 'mousemove',
         enterable:true,//鼠标是否可进入提示框浮层中
          formatter:formatterHover,//修改鼠标悬停显示的内容
    },
    color:["#c12e34", "#e6b600", "#0098d9",],
    textStyle:{
        fontFamily: "sans-serif",
        fontSize: 12,
        fontStyle: "normal",
        fontWeight: "normal",
    },
    legend: {
        data: ['DrugName', 'TargetGene', 'DiseaseLabel'] //此处的数据必须和关系网类别中name相对应  
    },
    series: [{
        type: 'graph',
        layout: 'force',     # 力导图
        animation: false,
        symbolSize: 25,
        label: {
            normal: {
                show: false,
                position: 'right',
                textStyle: {
                    fontSize: 10
                },
            },
        },
        labelLayout: {
            hideOverlap: true
        },
        draggable: true,
        roam: true,
        focusNodeAdjacency: true,
        force: {
            edgeLength: 80, //连线的长度  
            repulsion: 100, //子节点之间的间距  
            // gravity: 0.2
        },
        categories: categories,
        data: data.nodes,
        edges: data.edges,

        edgeSymbol: ['circle', 'arrow'],
        edgeSymbolSize: [4, 4],
        edgeLabel: {
            normal: {
                show: false,
                formatter: function (x) {
                    return x.data.relationship;
                },
                textStyle: {
                    fontSize: 10
                }
            }
        },
        lineStyle: {
            normal: {
                width: 2,
                color: '#4b565b',
            }
        },
    }]
};

剩下的就是把 data 和 edges 的数据传人即可。
同样可以用python进行请求获取

import requests
import json

login_url = 'http://localhost:7474/db/data/transaction/commit'
headers = {'Content-Type':'application/json'}
name_pwd = {'username':'neo4j',
      'password':'neo4j',
      }


def request_result(login_url, query_cql, headers):

    nodes, edges = [], []

    query_json = {
        "statements" : [ {
        "statement" : query_cql,
        "resultDataContents" : [ "row", "graph" ]
        }]
    }

    response = requests.post(url=login_url, json= query_json, headers=headers)
    print(response.status_code) 

    result = json.loads(response.text)['results'][0]['data']
    for i in range(len(result)):
        for n in result[i]['graph']['nodes']:
            if n not in nodes:
                nodes.append(n)

        for r in result[i]['graph']['relationships']:
            if r not in edges:
                edges.append(r)

    return nodes, edges


def query_all():
    query_cql = 'match p=()-->() return p'

    nodes, edges = request_result(login_url, query_cql, headers)
    
    return nodes, edges


## 修改成 Echarts 需要的格式
def buildNodes(nodeRecord):
    data = {"id": str(nodeRecord['id']), "label": next(iter(nodeRecord['labels']))}
    data.update(nodeRecord['properties'])

    tradeNames = data.get('TradeNames')
    if tradeNames and len(tradeNames) > 20:
        tradeNames = tradeNames[:20] + '...'
        data['TradeNames'] = tradeNames

    data['category'] = category_dict.get(data['label'])
    # newdata = {'name': data['name'], 'category': category_dict.get(data['label'])}
    return data

def buildEdges(relationRecord):
    data = {"source": str(relationRecord['startNode']), 
            "target": str(relationRecord['endNode']), 
            "relationship": relationRecord['type']}
    # return {"links": data}
    return data


nodes, edges = query_all()
nodes = [buildNodes(i) for i in nodes]
edges = [buildEdges(i) for i in edges]

整体前端框架参考

• https://github.com/chizhu/KGQA_HLM