go web app 7 mongodb query bson array

data contains bson array

//cmd

C:\Users\bob\golang3>go run main.go

student ID:  123

class ID: 456

grades:

exam :  100

quize :  100

homework :  100

homework :  100

package main

import (

"context"

"fmt"

"log"

"time"

"go.mongodb.org/mongo-driver/bson"

"go.mongodb.org/mongo-driver/mongo"

"go.mongodb.org/mongo-driver/mongo/options"

)

func main() {

client, err := mongo.NewClient(options.Client().ApplyURI("mongodb+srv://bob:password@cluster0.yvyo2.mongodb.net/test?retryWrites=true&w=majority"))

if err != nil {

log.Fatal(err)

}

ctx, _ := context.WithTimeout(context.Background(), 100*time.Second)

err = client.Connect(ctx)

if err != nil {

log.Fatal(err)

}

defer client.Disconnect(ctx)

filterCursor, err := gradesCollection.Find(ctx, bson.M{"student_id": 123, "class_id": 456})

defer filterCursor.Close(ctx)

if err != nil {

log.Fatal(err)

}

for filterCursor.Next(ctx) {

var grade bson.M

if err = filterCursor.Decode(&grade); err != nil {

log.Fatal(err)

}

fmt.Println("student ID: ", grade["student_id"])

fmt.Println("class ID:", grade["class_id"])

fmt.Println("grades: ")

scores := grade["scores"].(bson.A)

for _, score := range scores {

for k, v := range score.(bson.M) {

fmt.Println(k, ": ", v)

}

}

}

}

 

reference:

https://stackoverflow.com/questions/55870475/how-do-i-deserialize-output-from-mongo-go-driver-as-bson-array-into-a-interfac

http://chuanshuoge2.blogspot.com/2020/10/go-web-app-6-mongodb-insert.html

go map

https://blog.golang.org/maps