Get all model tree child node in MongoDB with Go

Question

I have data collection in MongoDB.

My data was built in model tree and relationship between child node and parent node is property parentid.

Here is my data architecture

And here is my sample data

{"_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"}

Now I want to get all child node of specific parent node. For example, I want to get all child node of DHBK node.

I have completed MongoDB shell to query this requirement.

Here is my 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(",")

It worked and showed me correct result. Here is my output result

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

Then I write Go code to implement this MongoDB shell.

Here is my code

 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
 }

But I have trouble implementing push, pop method and while loop as MongoDB shell by use Go.

Alex Blex · Accepted Answer · 2020-06-09 17:01:30Z

-1

Take a look if you are okay with $graphLookup limitations.

If so, you can do it dbside in a single aggregation query:

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}}
])

answered Jun 9, 2020 at 17:01

Alex Blex

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2 Comments

ThanhLam112358 Over a year ago

How to implement it to Go? sorry I have just beginner in Go and your shell is very complex

Alex Blex Over a year ago

collection_name.aggregate is collection.Pipe, the stages are bson.M docs. Try to write it one stage at a time, if it makes it easier.

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