Updating an Amazon DynamoDB Table Item

The following example uses the DynamoDB UpdateItem operation to update the rating to 0.5 for the item with the year 2015 and title The Big New Movie in the Movies table in your default region.

Create the file DynamoDBUpdateItem.go. Add the following statements to import the Go and AWS SDK for Go packages used in the example.

import (
    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/service/dynamodb"

    "fmt"
    "log"
)

Initialize a session that the SDK will use to load credentials from the shared credentials file ~/.aws/credentials and region from the shared configuration file ~/.aws/config and create a new DynamoDB service client.

// Initialize a session that the SDK will use to load
// credentials from the shared credentials file ~/.aws/credentials
// and region from the shared configuration file ~/.aws/config.
sess := session.Must(session.NewSessionWithOptions(session.Options{
    SharedConfigState: session.SharedConfigEnable,
}))

// Create DynamoDB client
svc := dynamodb.New(sess)

Call UpdateItem to add the item to the table. If we encounter an error, print the error message. Otherwise, display a message that the item was updated.

// Update item in table Movies
tableName := "Movies"
movieName := "The Big New Movie"
movieYear := "2015"
movieRating := "0.5"

input := &dynamodb.UpdateItemInput{
    ExpressionAttributeValues: map[string]*dynamodb.AttributeValue{
        ":r": {
            N: aws.String(movieRating),
        },
    },
    TableName: aws.String(tableName),
    Key: map[string]*dynamodb.AttributeValue{
        "Year": {
            N: aws.String(movieYear),
        },
        "Title": {
            S: aws.String(movieName),
        },
    },
    ReturnValues:     aws.String("UPDATED_NEW"),
    UpdateExpression: aws.String("set Rating = :r"),
}

_, err := svc.UpdateItem(input)
if err != nil {
    log.Fatalf("Got error calling UpdateItem: %s", err)
}

fmt.Println("Successfully updated '" + movieName + "' (" + movieYear + ") rating to " + movieRating)

See the complete example on GitHub.