使用 Go 连接图数据库

最近更新时间：2023-02-23 17:58:14
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 本文介绍如何使用 Go 语言连接和操作图数据库 KonisGraph。以 Gremlin-console tutorials 中的人和软件的关系图为示例。
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如图所示，整个图包含2类点 person 和 software，2类边 knows 和 created，和几类属性 id、name、age、lang、weight。
环境准备
1. 安装 Go 语言环境，参考 Go 语言官网。
2. 获取图数据库的连接参数。在 控制台 实例详情页中可以查看实例的 VIP 和 PORT，即内网地址和 Gremlin 端口。
示例程序
新建一个 demo 目录，并初始化 module
mkdir graph_demo
cd graph_demo
go mod init demo
示例项目目录结构
|- graph_demo
    |- go.mod
    |- go.sum
    |- main.go
    |- model
        |- meta.go
        |- property.go
        |- vertex.go
        |- edge.go
定义点、边及属性等模型
meta.go: 属性、点边等对应的元数据定义
package model
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type PropertyType string
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const (
    PropertyLong   = "T_LONG"
    PropertyInt    = "T_INT"
    PropertyInt64  = "T_INT64"
    PropertyString = "T_STRING"
    PropertyDouble = "T_DOUBLE"
)
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type PropertyMeta struct {
    Label   string
    Type    PropertyType
    Default string
}
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type VertexMeta struct {
    Label      string
    Primary    string
    Properties []string
}
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type EdgeMeta struct {
    Label          string
    SrcVertexLabel string
    DstVertexLabel string
    Properties     []string
}
property.go: 属性模型定义
package model
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type Property struct {
    Type  string        `json:"@type"`
    Value PropertyValue `json:"@Value"`
}
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type PropertyValue struct {
    Key   string      `json:"key"`
    Value interface{} `json:"value"`
}
vertex.go: 点模型定义
package model
﻿
import "encoding/json"
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type VertexList struct {
    listOfVertices List
    Vertices       []Vertex
}
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type List struct {
    Type  string        `json:"@type"`
    Value []interface{} `json:"@value"`
}
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type Vertex struct {
    Type  string      `json:"@type"`
    Value VertexValue `json:"@value"`
}
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type VertexValue struct {
    ID         interface{}           `json:"id"`
    Label      string                `json:"label"`
    Properties map[string][]Property `json:"properties,omitempty"`
}
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func (vl *VertexList) UnmarshalJSON(data []byte) error {
    if err := json.Unmarshal(data, &vl.listOfVertices); err == nil {
        if data, err = json.Marshal(vl.listOfVertices.Value); err != nil {
            return err
        }
    }
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    return json.Unmarshal(data, &vl.Vertices)
}
edge.go: 边模型定义
package model
﻿
import "encoding/json"
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type EdgeList struct {
    listOfEdges List
    Edges       []Edge
}
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type Edge struct {
    Type  string    `json:"@type"`
    Value EdgeValue `json:"@value"`
}
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type EdgeValue struct {
    ID         interface{}           `json:"id"`
    Label      string                `json:"label"`
    InVLabel   string                `json:"inVLabel,omitempty"`
    OutVLabel  string                `json:"outVLabel,omitempty"`
    InV        interface{}           `json:"inV,omitempty"`
    OutV       interface{}           `json:"outV,omitempty"`
    Properties map[string][]Property `json:"properties,omitempty"`
}
﻿
func (el *EdgeList) UnmarshalJSON(data []byte) error {
    if err := json.Unmarshal(data, &el.listOfEdges); err == nil {
        if data, err = json.Marshal(el.listOfEdges.Value); err != nil {
            return err
        }
    }
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    return json.Unmarshal(data, &el.Edges)
}
数据库操作
package main
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import (
    "fmt"
    "log"
    "strings"
    "tutorial/model"
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    "github.com/northwesternmutual/grammes"
)
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type Tutorial struct {
    *grammes.Client
}
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func New(host string, port int, username, password string) (*Tutorial, error) {
    url := fmt.Sprintf("ws://%s:%d", host, port)
    c, err := grammes.DialWithWebSocket(url, grammes.WithAuthUserPass(username, password))
    if err != nil {
        return nil, err
    }
    return &Tutorial{Client: c}, nil
}
﻿
func (t *Tutorial) CreatePropertyMetas(metas ...model.PropertyMeta) error {
    for _, meta := range metas {
        expr := fmt.Sprintf(`s.addP("%s", "%s", "%s")`, meta.Label, meta.Type, meta.Default)
        _, err := t.ExecuteStringQuery(expr)
        if err != nil {
            return err
        }
    }
    return nil
}
﻿
func (t *Tutorial) CreateVertexMetas(metas ...model.VertexMeta) error {
    for _, meta := range metas {
        expr := fmt.Sprintf(`s.addV("%s", "%s", ["%s"])`, meta.Label, meta.Primary, strings.Join(meta.Properties, "\\",\\""))
        _, err := t.ExecuteStringQuery(expr)
        if err != nil {
            return err
        }
    }
    return nil
}
﻿
func (t *Tutorial) CreateEdgeMetas(metas ...model.EdgeMeta) error {
    for _, meta := range metas {
        expr := fmt.Sprintf(`s.addE("%s", "%s", "%s", ["%s"])`, meta.Label, meta.SrcVertexLabel, meta.DstVertexLabel,
            strings.Join(meta.Properties, "\\",\\""))
        _, err := t.ExecuteStringQuery(expr)
        if err != nil {
            return err
        }
    }
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    return nil
}
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func createMetas(tutorial *Tutorial) {
    propMetas := []model.PropertyMeta{
        {Label: "id", Type: model.PropertyLong, Default: "0"},
        {Label: "name", Type: model.PropertyString, Default: ""},
        {Label: "age", Type: model.PropertyInt, Default: "0"},
        {Label: "weight", Type: model.PropertyDouble, Default: "0.0"},
        {Label: "lang", Type: model.PropertyString, Default: ""},
    }
    if err := tutorial.CreatePropertyMetas(propMetas...); err != nil {
        log.Fatal("create property meta err ", err)
    }
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    vertexMetas := []model.VertexMeta{
        {Label: "person", Primary: "id", Properties: []string{"name", "age"}},
        {Label: "software", Primary: "id", Properties: []string{"name", "lang"}},
    }
    if err := tutorial.CreateVertexMetas(vertexMetas...); err != nil {
        log.Fatal("create vertex meta err ", err)
    }
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    edgeMetas := []model.EdgeMeta{
        {Label: "knows", SrcVertexLabel: "person", DstVertexLabel: "person", Properties: []string{"weight"}},
        {Label: "created", SrcVertexLabel: "person", DstVertexLabel: "software", Properties: []string{"weight"}},
    }
    if err := tutorial.CreateEdgeMetas(edgeMetas...); err != nil {
        log.Fatal("create edge meta err ", err)
    }
}
﻿
func addVertexAndEdge(tutorial *Tutorial) {
	//添加点
	//添加点 person,其中 id=1,属性 name=marko,age=29
	_, err := tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('age', AGE) ", map[string]string{"ID": "1", "LABEL": "person", "NAME": "marko", "AGE": "29"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加点 person,其中 id=2,属性 name=vadas,age=27
	_, err = tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('age', AGE) ", map[string]string{"ID": "2", "LABEL": "person", "NAME": "vadas", "AGE": "27"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加点 person,其中 id=4,属性 name=josh,age=32
	_, err = tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('age', AGE) ", map[string]string{"ID": "4", "LABEL": "person", "NAME": "josh", "AGE": "32"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加点 person,其中 id=6,属性 name =peter,age=35
	_, err = tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('age', AGE) ", map[string]string{"ID": "6", "LABEL": "person", "NAME": "peter", "AGE": "35"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加点 software,其中 id=3,属性 name=lop,lang=java
	_, err = tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('lang', LANG) ", map[string]string{"ID": "3", "LABEL": "software", "NAME": "lop", "LANG": "java"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加点 software,其中 id=5,属性 name=ripple,lang=java
	_, err = tutorial.ExecuteBoundStringQuery("g.addV(LABEL).property(id, ID).property('name', NAME).property('lang', LANG) ", map[string]string{"ID": "5", "LABEL": "software", "NAME": "ripple", "LANG": "java"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
﻿
	//添加边
	//添加边 knows,其中起点 id 为1,终点 id 为2
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)) ", map[string]string{"LABEL": "knows", "SRC": "1", "DST": "2"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加边 knows,其中起点 id 为1,终点 id 为4
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)) ", map[string]string{"LABEL": "knows", "SRC": "1", "DST": "4"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加边 created,其中起点 id 为1,终点 id 为3,属性 weight=0.4
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)).property('weight', WEIGHT) ", map[string]string{"LABEL": "created", "SRC": "1", "DST": "3", "WEIGHT": "0.4"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加边 created,其中起点 id 为6,终点 id 为3,属性 weight=0.2
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)).property('weight', WEIGHT) ", map[string]string{"LABEL": "created", "SRC": "6", "DST": "3", "WEIGHT": "0.2"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加边 created,其中起点 id 为4,终点 id 为3,属性 weight=0.4
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)).property('weight', WEIGHT) ", map[string]string{"LABEL": "created", "SRC": "4", "DST": "3", "WEIGHT": "0.4"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
	//添加边 created,其中起点 id 为4,终点 id 为5,属性 weight=1.0
	_, err = tutorial.ExecuteBoundStringQuery("g.V(SRC).addE(LABEL).to(V(DST)).property('weight', WEIGHT) ", map[string]string{"LABEL": "created", "SRC": "4", "DST": "5", "WEIGHT": "1.0"}, map[string]string{})
	if err != nil {
		log.Fatal("ExecuteBoundStringQuery addV err ", err)
	}
}
﻿
func main() {
    tutorial, err := New("KONISGRAPH_VIP", KONISGRAPH_PORT, "your useranme", "your password")
    //KONISGRAPH_VIP 图数据库 KonisGraph 实例的内网地址 vip，如 10.xx.xx.107
    //KONISGRAPH_PORT 图数据库 KonisGraph 实例的 Gremlin 端口，如 8186
    if err != nil {
        log.Fatal("open gremlin connection err ", err)
    }
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    // 创建属性、点、边等元数据
    createMetas(tutorial)
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    // 添加点和边
    addVertexAndEdge(tutorial)
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    // 做一些查询
    // 查看 marko 的信息
	data, _ := tutorial.ExecuteBoundStringQuery("g.V().hasLabel(LABEL).has('name', NAME).valueMap()", map[string]string{"LABEL": "person", "NAME": "marko"}, map[string]string{})
	for _, item := range data {
		log.Println(string(item))
	}
	// 查找 marko 都认识哪些人
	data, _ = tutorial.ExecuteBoundStringQuery("g.V().hasLabel(LABEL).has('name', NAME).out(OUT_LABEL)", map[string]string{"LABEL": "person", "NAME": "marko","OUT_LABEL":"knows"}, map[string]string{})
	for _, item := range data {
		var vertices model.VertexList
		if err := vertices.UnmarshalJSON(item); err != nil {
			log.Fatal("unmarshal resp err: ", err)
		}
		var names []interface{}
		for _, vertex := range vertices.Vertices {
			names = append(names, vertex.Value.Properties["name"][0].Value.Value)
		}
		log.Print("Who marko knows: ", names)
	}
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	// 查找哪些人创建了软件 lop
	data, _ = tutorial.ExecuteBoundStringQuery("g.V().hasLabel(LABEL).has('name', NAME).in(IN_LABEL)", map[string]string{"LABEL": "software", "NAME": "lop","IN_LABEL":"created"}, map[string]string{})
	for _, item := range data {
		var vertices model.VertexList
		if err := vertices.UnmarshalJSON(item); err != nil {
			log.Fatal("unmarshal resp err: ", err)
		}
		var names []interface{}
		for _, vertex := range vertices.Vertices {
			names = append(names, vertex.Value.Properties["name"][0].Value.Value)
		}
		log.Println("Who creates software lop: ", names)
	}
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	// 统计点数量, 返回值为数组,转 string 后为 {"@type":"g:List","@value":[{"@type":"g:Int64","@value":9999999999}]},真正的返回值为 value 后的9999999999,需要自己处理，其他非点边返回数据处理方式类似
	data, _ = tutorial.ExecuteBoundStringQuery("g.V().count()", map[string]string{}, map[string]string{})
	for _, item := range data {
		log.Println("Who creates software lop: ", string(item))
	}
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	//关闭客户端,客户端可复用
	tutorial.Close()
}
运行示例程序
go run main.go
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