Go 言語でデータベース関数を学習し、MongoDB クラスターで読み取りおよび書き込み操作を実装します。

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

import (
    "context"
    "fmt"
    "log"
    "time"

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

const (
    ConnectionString = "mongodb://localhost:27017,localhost:27018,localhost:27019/?replicaSet=myReplicaSet"
    DatabaseName     = "myDatabase"
    CollectionName   = "myCollection"
)

func main() {
    // 设置客户端连接配置
    clientOptions := options.Client().ApplyURI(ConnectionString)

    // 连接到MongoDB
    client, err := mongo.Connect(context.Background(), clientOptions)
    if err != nil {
        log.Fatal(err)
    }

    // 检查连接
    err = client.Ping(context.Background(), nil)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println("Connected to MongoDB!")

    // 获取数据库和集合
    database := client.Database(DatabaseName)
    collection := database.Collection(CollectionName)

    // 插入文档
    doc := bson.D{
        {Key: "name", Value: "Alice"},
        {Key: "age", Value: 20},
    }
    insertResult, err := collection.InsertOne(context.Background(), doc)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Inserted ID:", insertResult.InsertedID)

    // 查询文档
    filter := bson.D{{Key: "name", Value: "Alice"}}
    var result bson.M
    err = collection.FindOne(context.Background(), filter).Decode(&result)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Find One Result:", result)

    // 更新文档
    update := bson.D{{Key: "$set", Value: bson.D{{Key: "age", Value: 21}}}}
    updateResult, err := collection.UpdateOne(context.Background(), filter, update)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Updated Count:", updateResult.ModifiedCount)

    // 删除文档
    deleteResult, err := collection.DeleteOne(context.Background(), filter)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Deleted Count:", deleteResult.DeletedCount)

    // 断开连接
    err = client.Disconnect(context.Background())
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Disconnected from MongoDB!")
}