Go: using MongoDB

  • Go
  • Gabriele Romanato

MongoDB is a widely used NoSQL database for handling unstructured and semi-structured data. Go, also known as Golang, is an open-source programming language that has gained popularity for its efficiency and ease of use. Combining MongoDB with Go can lead to powerful and efficient data management solutions. In this article, well explore how to use MongoDB in Go to create, read, update, and delete documents in the database.

Prerequisites

Before you begin, its important to make sure you have Go and MongoDB properly installed on your system. In addition, you can use the official library of MongoDB for Go called "mongo-go-driver", which greatly simplifies the interaction with the database.

Installing the MongoDB Go driver

To install the MongoDB Go driver, open a terminal and run the following command using the Go package manager, known as "go get": 

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

Once the installation is complete, youre ready to start coding to interact with MongoDB using Go.

Database connection

Lets start with connecting to the MongoDB database using the driver we just installed. Here is an example of how to do it: 


package main

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

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

func main() {
	// Configurazione del client MongoDB
	clientOptions := options.Client().ApplyURI("mongodb://localhost:27017")
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	client, err := mongo.Connect(ctx, clientOptions)
	if err != nil {
		log.Fatal(err)
	}

	// Verifica della connessione
	err = client.Ping(ctx, nil)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Connessione a MongoDB riuscita!")

	// Chiusura della connessione quando non è più necessaria
	defer func() {
		if err = client.Disconnect(ctx); err != nil {
			log.Fatal(err)
		}
		fmt.Println("Connessione a MongoDB chiusa.")
	}()
}

In this example, were setting up a MongoDB client using the default connection URI "mongodb://localhost:27017". Next, we use Connect to establish the connection and Ping to verify success. Finally, it is important to close the connection using Disconnect when it is no longer needed.

CRUD operations with MongoDB and Go

Once the connection is established, you can perform CRUD (Create, Read, Update, Delete) operations on the documents in the database. Examples of each operation are provided below.

Creating a document 


collection := client.Database("testdb").Collection("users")

user := bson.D{
    {Key: "name", Value: "Alice"},
    {Key: "age", Value: 30},
}

_, err = collection.InsertOne(ctx, user)
if err != nil {
    log.Fatal(err)
}

fmt.Println("Documento creato:", user)

Reading a document 


var result bson.M
filter := bson.M{"name": "Alice"}

err = collection.FindOne(ctx, filter).Decode(&result)
if err != nil {
    log.Fatal(err)
}

fmt.Println("Documento trovato:", result)

Updating a document 


filter := bson.M{"name": "Alice"}
update := bson.M{"$set": bson.M{"age": 31}}

updateResult, err := collection.UpdateOne(ctx, filter, update)
if err != nil {
    log.Fatal(err)
}

fmt.Printf("Documenti modificati: %v\n", updateResult.ModifiedCount)

Deleting a document 


deleteResult, err := collection.DeleteOne(ctx, filter)
if err != nil {
    log.Fatal(err)
}

fmt.Printf("Documenti eliminati: %v\n", deleteResult.DeletedCount)

Conclusions

In this article, weve explored how to use MongoDB in conjunction with the Go programming language. Weve learned how to connect to a MongoDB database, perform CRUD operations, and manage documents. The combination of MongoDB and Go offers a powerful solution for managing data efficiently and flexibly. Leveraging the "mongo-go-driver" driver, you can build robust applications that interact with MongoDB smoothly.

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