使用Go获取MongoDB中的所有模型树子节点

Question

我在MongoDB中有数据收集。

我的数据是在模型树中构建的，child node和parent node之间的关系是属性parentid。

这是我的数据体系结构

这是我的示例数据

{"_id":{"$oid":"5ebd05b52f3700008500220b"},"username":"DHBK","password":"123456","lastname":"DHBK","useremail":"[email protected]","usertel":"0907111001","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":null,"comid":"DHBK","comdepartment":"DHBK","usercode":"DHBK_0001","usertype":"ADMIN_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500220c"},"username":"KHOA_DIEN","password":"123456","lastname":"KHOA_DIEN","useremail":"[email protected]","usertel":"0907111002","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"DHBK","comid":"DHBK","comdepartment":"KHOA_DIEN","usercode":"DHBK_0002","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500220d"},"username":"KHOA_XD","password":"123456","lastname":"KHOA_XD","useremail":"[email protected]","usertel":"0907111003","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"DHBK","comid":"DHBK","comdepartment":"KHOA_XD","usercode":"DHBK_0003","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500220e"},"username":"KHOA_CNTT","password":"123456","lastname":"KHOA_CNTT","useremail":"[email protected]","usertel":"0907111004","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"DHBK","comid":"DHBK","comdepartment":"KHOA_CNTT","usercode":"DHBK_0004","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500220f"},"username":"BOMON_TUDONG","password":"123456","lastname":"BOMON_TUDONG","useremail":"[email protected]","usertel":"0907111005","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_DIEN","comid":"DHBK","comdepartment":"KHOA_DIEN","usercode":"DHBK_0005","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002210"},"username":"BOMON_VIENTHONG","password":"123456","lastname":"BOMON_VIENTHONG","useremail":"[email protected]","usertel":"0907111006","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_DIEN","comid":"DHBK","comdepartment":"KHOA_DIEN","usercode":"DHBK_0006","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002211"},"username":"BOMON_HETHONG","password":"123456","lastname":"BOMON_HETHONG","useremail":"[email protected]","usertel":"0907111007","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_DIEN","comid":"DHBK","comdepartment":"KHOA_DIEN","usercode":"DHBK_0007","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002212"},"username":"BOMON1_XD","password":"123456","lastname":"BOMON1_XD","useremail":"[email protected]","usertel":"0907111008","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_XD","comid":"DHBK","comdepartment":"KHOA_XD","usercode":"DHBK_0008","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002213"},"username":"BOMON2_XD","password":"123456","lastname":"BOMON2_XD","useremail":"[email protected]","usertel":"0907111009","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_XD","comid":"DHBK","comdepartment":"KHOA_XD","usercode":"DHBK_0009","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002214"},"username":"BOMON3_XD","password":"123456","lastname":"BOMON3_XD","useremail":"[email protected]","usertel":"0907111010","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_XD","comid":"DHBK","comdepartment":"KHOA_XD","usercode":"DHBK_0010","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002215"},"username":"TRUONGKHOA_BMVT","password":"123456","lastname":"TRUONGKHOA_BMVT","useremail":"[email protected]","usertel":"0907111011","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"BOMON_VIENTHONG","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0011","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002216"},"username":"PHOKHOA_BMVT","password":"123456","lastname":"PHOKHOA_BMVT","useremail":"[email protected]","usertel":"0907111012","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"BOMON_VIENTHONG","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0012","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002217"},"username":"THUKY_BMVT","password":"123456","lastname":"THUKY_BMVT","useremail":"[email protected]","usertel":"0907111013","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"BOMON_VIENTHONG","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0013","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002218"},"username":"GV_BMVT","password":"123456","lastname":"GV_BMVT","useremail":"[email protected]","usertel":"0907111014","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"BOMON_VIENTHONG","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0014","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f37000085002219"},"username":"SV1_BMVT","password":"123456","lastname":"SV1_BMVT","useremail":"[email protected]","usertel":"0907111015","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0015","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500221a"},"username":"SV2_BMVT","password":"123456","lastname":"SV2_BMVT","useremail":"[email protected]","usertel":"0907111016","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0016","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500221b"},"username":"SV3_BMVT","password":"123456","lastname":"SV3_BMVT","useremail":"[email protected]","usertel":"0907111017","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0017","usertype":"USER_COM"}
{"_id":{"$oid":"5ebd05b52f3700008500221c"},"username":"SV4_BMVT","password":"123456","lastname":"SV4_BMVT","useremail":"[email protected]","usertel":"0907111018","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0018","usertype":"USER_COM"}
{"_id":{"$oid":"5ec642b2412b0000e70021a5"},"username":"KHOA_KT","password":"123456","lastname":"KHOA_KT","useremail":"[email protected]","usertel":"0907111002","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"DHKT","comid":"DHBK","comdepartment":"KHOA_KT","usercode":"DHKT_0002","usertype":"USER_COM"}
{"_id":{"$oid":"5ec642b2412b0000e70021a8"},"username":"BOMON_KTDOANHNGHIEP","password":"123456","lastname":"BOMON_KTDOANHNGHIEP","useremail":"[email protected]","usertel":"0907111005","userdate":"2020-05-05","userstatus":"ACTIVE","userparentid":"KHOA_KT","comid":"DHBK","comdepartment":"KHOA_KT","usercode":"DHKT_0005","usertype":"USER_COM"}
{"_id":{"$oid":"5ece3517b8d5570916d013f6"},"username":"SV5_BMVT","password":"123","lastname":"SV5_BMVT","useremail":"[email protected]","usertel":"0907111019","userdate":"2020-05-14","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0019","usertype":"USER_COM"}
{"_id":{"$oid":"5eddf0a9b8d5570916dae6ff"},"username":"SV6_BMVT","password":"123456","lastname":"SV6_BMVT","useremail":"[email protected]","usertel":"0907111020","userdate":"2020-06-08","userstatus":"ACTIVE","userparentid":"GV_BMVT","comid":"DHBK","comdepartment":"BOMON_VIENTHONG","usercode":"DHBK_0019","usertype":"USER_COM"}

现在，我要获取特定父节点的所有子节点。例如，我要获取DHBK node的所有子节点。

我已经完成MongoDB shell来查询此要求。

这是我的MongoDB Shell

var descendants=[]
var stack=[];
var item = db.users.findOne({username:"DHBK"});
stack.push(item);
while (stack.length>0){
    var currentnode = stack.pop();
    var children = db.users.find({userparentid:currentnode.username});
    while(true === children.hasNext()) {
        var child = children.next();
        descendants.push(child.username);
        stack.push(child);
    }
}
descendants.join(",")

它起作用了，并向我显示了正确的结果。这是我的输出结果

KHOA_DIEN,KHOA_XD,KHOA_CNTT,BOMON1_XD,BOMON2_XD,BOMON3_XD,BOMON_TUDONG,BOMON_VIENTHONG,BOMON_HETHONG,TRUONGKHOA_BMVT,PHOKHOA_BMVT,THUKY_BMVT,GV_BMVT,SV1_BMVT,SV2_BMVT,SV3_BMVT,SV4_BMVT,SV5_BMVT,SV6_BMVT

然后我编写Go代码来实现此MongoDB Shell。

这是我的代码

 package main
 import (
     "context"
     "fmt"
     "strings"
     "time"
     "go.mongodb.org/mongo-driver/bson"
     "go.mongodb.org/mongo-driver/mongo"
     "go.mongodb.org/mongo-driver/mongo/options"
 )
 func main() {
      GetAllChildOfNode("DHBK")
 }
func GetAllChildOfNode(node string) error {
   ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
   client, err := mongo.Connect(ctx, options.Client().ApplyURI("URI string"))
   if err != nil {
       return err
   }
   defer client.Disconnect(ctx)
   database := client.Database("users")
   users := database.Collection("users")
   var descendants []string
   var stack []string
   err = users.FindOne(ctx, bson.M{"username": "DHBK"}).Decode(&stack)
   leng := len(stack)
   for leng > 0 {
       //I HaVE TROUBLE HERE
       currentnode := stack.
   }
   return nil
 }

但是我在使用Go将push，pop方法和while loop实现为MongoDB shell时遇到了麻烦。预先谢谢你。

Answer 1

[如果您对$graphLookup的限制没问题，请看一下。

如果是这样，您可以在单个聚合查询中执行dbside：

db.collection_name.aggregate([
  {$match: {username: "DHBK"}}, // select root document
  {
    $graphLookup: {             // load the tree as embedded docs
      from: "collection_name",
      startWith: "$username",
      connectFromField: "username",
      connectToField: "userparentid",
      as: "descendants",
    }
  },
  {$project: {                  // add root element if needed
      descendants: {$concatArrays: [["$$ROOT"], "$descendants"] }
  }},
  {$unwind: "$descendants"},    // final formatting steps
  {$replaceRoot: {newRoot: "$descendants"}},
  {$project: {descendants:0}}
])