使用Go获取MongoDB中所有模型树子节点

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我在 mongodb 中收集数据。

我的数据是在模型树中构建的，子节点和父节点之间的关系是属性parentid。

这是我的数据架构

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"}

现在我想获取特定父节点的所有子节点。比如我想获取dhbk节点的所有子节点。

我已经完成了 mongodb shell 来查询这个需求。

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(",")

它有效并显示了正确的结果。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 代码来实现这个 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 作为 mongodb shell 实现时遇到了麻烦。

解决方案

看看您是否同意 $graphLookup 的限制。

如果是这样，您可以在单个聚合查询中在数据库端执行此操作：

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}}
])

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