Cayley圖數據庫的可視化（Visualize）

時間 2019-12-14

原文原文鏈接

引入

在文章Cayley圖數據庫的簡介及使用中，咱們已經瞭解了Cayley圖數據庫的安裝、數據導入以及進行查詢等。
Cayley圖數據庫是Google開發的開源圖數據庫，雖然功能尚未Neo4J來得那麼強大，但也有不少新的功能等待着咱們去探索。本文將繼續上篇文章的旅程，給讀者介紹如何在Cayley圖數據庫中實現查詢結果的可視化。
下面，讓咱們一塊兒來探究Cayley的奧祕吧~html

查詢結果可視化

Cayley圖數據庫的查詢語句的參考網址爲：https://github.com/cayleygraph/cayley/blob/master/docs/GizmoAPI.md 。若想實現查詢結果的可視化，則須要使用Tag()函數，返回的結果樣式應當以下：node

[
{
  "source": "node1",
  "target": "node2"
},
{
  "source": "node1",
  "target": "node3"
},
]

即返回的結果中對節點會打上Tag，source爲來源，顏色爲藍色，target爲目的地，顏色爲橙色。
咱們使用的數據仍來自文章Cayley圖數據庫的簡介及使用。首先導入數據：git

./cayley load -c cayley_example.yml -i data/China_Movie.nq

接着啓動查詢語句的web界面：github

./cayley http -i ./data/China_Movie.nq -d memstore --host=:64210

在瀏覽器中輸入網址：http://localhost:64210 ，選擇Visualize，web

輸入命令：算法

g.V('<沈騰>').Tag("source").Out('<ACT_IN>').Tag("target").All();

就能能到關係圖的可視化結果了，以下：數據庫

接着咱們來查看某個實體的全部屬性及屬性值，輸入的命令以下：json

var eq = "<流浪地球>";
var attrs = g.V(eq).OutPredicates().ToArray(); 

values = new Array();
for (i in attrs) {
    var value = g.V(eq).Out(attrs[i]).ToValue();
    values[i] = value;
}

var s = new Array();


for (i in attrs) {
  var key_val_json = new Object();
  key_val_json["id"] = values[i];
  key_val_json["source"] = eq;
  key_val_json["target"]= attrs[i]+":"+values[i];
  s[i] = key_val_json;
}

for (i =0; i< s.length; i++) {
    g.Emit(s[i]);
}

出來的圖以下：數組

這樣咱們就實現了Cayley圖數據庫的可視化，可是效果通常，並且不支持對邊賦值，所以沒法在邊上顯示關係。瀏覽器

利用D3.js實現可視化展現

利用D3.js，咱們能夠把查詢到的結果，本身來畫關係圖。筆者主要參考的項目的Github地址爲： https://github.com/ownthink/KG-View/blob/master/index.html 。咱們只須要將查詢到的結果複製粘貼到該HTML文件中便可。仍是以《流浪地球》的全部屬性及屬性值爲例，查詢的命令以下：

var eq = "<流浪地球>";
var attrs = g.V(eq).OutPredicates().ToArray(); 

values = new Array();
for (i in attrs) {
    var value = g.V(eq).Out(attrs[i]).ToValue();
    values[i] = value;
}

var s = new Array();

for (i in attrs) {
  var key_val_json = new Object();
  key_val_json["source"] = eq;
  key_val_json["rela"] = attrs[i];
  key_val_json["target"] = values[i];
  key_val_json["type"] = "resolved";
  s[i] = key_val_json;
}

for (i =0; i< s.length; i++) {
    g.Emit(s[i]);
}

返回的結果以下：

{
    "result": [
        {
            "rela": "<ISA>",
            "source": "<流浪地球>",
            "target": "<Movie>",
            "type": "resolved"
        },
        {
            "rela": "<rank>",
            "source": "<流浪地球>",
            "target": "2",
            "type": "resolved"
        },
        {
            "rela": "<src>",
            "source": "<流浪地球>",
            "target": "/item/%E6%B5%81%E6%B5%AA%E5%9C%B0%E7%90%83",
            "type": "resolved"
        },
        {
            "rela": "<box_office>",
            "source": "<流浪地球>",
            "target": "40.83億",
            "type": "resolved"
        },
        {
            "rela": "<avg_price>",
            "source": "<流浪地球>",
            "target": "46",
            "type": "resolved"
        },
        {
            "rela": "<avg_people>",
            "source": "<流浪地球>",
            "target": "50",
            "type": "resolved"
        },
        {
            "rela": "<begin_date>",
            "source": "<流浪地球>",
            "target": "2019.02.05",
            "type": "resolved"
        }
    ]
}

將result的結果數組複製粘貼至index.html文件，內容以下：

<!DOCTYPE html>
<meta charset="utf-8">
<style>.link {  fill: none;  stroke: #666;  stroke-width: 1.5px;}#licensing {  fill: green;}.link.licensing {  stroke: green;}.link.resolved {  stroke-dasharray: 0,2 1;}circle {  fill: #ccc;  stroke: #333;  stroke-width: 1.5px;}text {  font: 12px Microsoft YaHei;  pointer-events: none;  text-shadow: 0 1px 0 #fff, 1px 0 0 #fff, 0 -1px 0 #fff, -1px 0 0 #fff;}.linetext {    font-size: 12px Microsoft YaHei;}</style>
<body>
<script src="https://d3js.org/d3.v3.min.js"></script>
<script>
var links = 
[
    {
      "rela": "<ISA>",
      "source": "<流浪地球>",
      "target": "<Movie>",
      "type": "resolved"
    },
    {
      "rela": "<rank>",
      "source": "<流浪地球>",
      "target": "2",
      "type": "resolved"
    },
    {
      "rela": "<src>",
      "source": "<流浪地球>",
      "target": "/item/%E6%B5%81%E6%B5%AA%E5%9C%B0%E7%90%83",
      "type": "resolved"
    },
    {
      "rela": "<box_office>",
      "source": "<流浪地球>",
      "target": "40.83億",
      "type": "resolved"
    },
    {
      "rela": "<avg_price>",
      "source": "<流浪地球>",
      "target": "46",
      "type": "resolved"
    },
    {
      "rela": "<avg_people>",
      "source": "<流浪地球>",
      "target": "50",
      "type": "resolved"
    },
    {
      "rela": "<begin_date>",
      "source": "<流浪地球>",
      "target": "2019.02.05",
      "type": "resolved"
    }
];
var nodes = {};
links.forEach(function(link)
{
  link.source = nodes[link.source] || (nodes[link.source] = {name: link.source});
  link.target = nodes[link.target] || (nodes[link.target] = {name: link.target});
});
var width = 1920, height = 1080;
var force = d3.layout.force()
    .nodes(d3.values(nodes))
    .links(links)
    .size([width, height])
    .linkDistance(180)
    .charge(-1500)
    .on("tick", tick)
    .start();
var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);
var marker=
    svg.append("marker")
    .attr("id", "resolved")
    .attr("markerUnits","userSpaceOnUse")
    .attr("viewBox", "0 -5 10 10")
    .attr("refX",32)
    .attr("refY", -1)
    .attr("markerWidth", 12)
    .attr("markerHeight", 12)
    .attr("orient", "auto")
    .attr("stroke-width",2)
    .append("path")
    .attr("d", "M0,-5L10,0L0,5")
    .attr('fill','#000000');
var edges_line = svg.selectAll(".edgepath")
    .data(force.links())
    .enter()
    .append("path")
    .attr({
          'd': function(d) {return 'M '+d.source.x+' '+d.source.y+' L '+ d.target.x +' '+d.target.y},
          'class':'edgepath',
          'id':function(d,i) {return 'edgepath'+i;}})
    .style("stroke",function(d){
         var lineColor;
         lineColor="#B43232";
         return lineColor;
     })
    .style("pointer-events", "none")
    .style("stroke-width",0.5)
    .attr("marker-end", "url(#resolved)" );
var edges_text = svg.append("g").selectAll(".edgelabel")
.data(force.links())
.enter()
.append("text")
.style("pointer-events", "none")
.attr({  'class':'edgelabel',
               'id':function(d,i){return 'edgepath'+i;},
               'dx':80,
               'dy':0
               });
edges_text.append('textPath')
.attr('xlink:href',function(d,i) {return '#edgepath'+i})
.style("pointer-events", "none")
.text(function(d){return d.rela;});
var circle = svg.append("g").selectAll("circle")
    .data(force.nodes())
    .enter().append("circle")
    .style("fill",function(node){
        var color;
        var link=links[node.index];
        color="#F9EBF9";
        return color;
    })
    .style('stroke',function(node){ 
        var color;
        var link=links[node.index];
        color="#A254A2";
        return color;
    })
    .attr("r", 28)
    .on("click",function(node)
    {
        edges_line.style("stroke-width",function(line){
            console.log(line);
            if(line.source.name==node.name || line.target.name==node.name){
                return 4;
            }else{
                return 0.5;
            }
        });
    })
    .call(force.drag);
var text = svg.append("g").selectAll("text")
    .data(force.nodes())
    .enter()
    .append("text")
    .attr("dy", ".35em")  
    .attr("text-anchor", "middle")
    .style('fill',function(node){
        var color;
        var link=links[node.index];
        color="#A254A2";
        return color;
    }).attr('x',function(d){
        var re_en = /[a-zA-Z]+/g;
        if(d.name.match(re_en)){
             d3.select(this).append('tspan')
             .attr('x',0)
             .attr('y',2)
             .text(function(){return d.name;});
        }
        
        else if(d.name.length<=4){
             d3.select(this).append('tspan')
            .attr('x',0)
            .attr('y',2)
            .text(function(){return d.name;});
        }else{
            var top=d.name.substring(0,4);
            var bot=d.name.substring(4,d.name.length);
            d3.select(this).text(function(){return '';});
            d3.select(this).append('tspan')
                .attr('x',0)
                .attr('y',-7)
                .text(function(){return top;});
            d3.select(this).append('tspan')
                .attr('x',0)
                .attr('y',10)
                .text(function(){return bot;});
        }
    });
function tick() {
  circle.attr("transform", transform1);
  text.attr("transform", transform2);
  edges_line.attr('d', function(d) { 
      var path='M '+d.source.x+' '+d.source.y+' L '+ d.target.x +' '+d.target.y;
      return path;
  });  
    
  edges_text.attr('transform',function(d,i){
        if (d.target.x<d.source.x){
            bbox = this.getBBox();
            rx = bbox.x+bbox.width/2;
            ry = bbox.y+bbox.height/2;
            return 'rotate(180 '+rx+' '+ry+')';
        }
        else {
            return 'rotate(0)';
        }
   });
}
function linkArc(d) {
  return 'M '+d.source.x+' '+d.source.y+' L '+ d.target.x +' '+d.target.y
}
function transform1(d) {
  return "translate(" + d.x + "," + d.y + ")";
}
function transform2(d) {
      return "translate(" + (d.x) + "," + d.y + ")";
}
</script>

在瀏覽器中打開，效果以下：

這個繪圖的效果會比Cayley自帶的效果好一些，但功能仍是有限。