AWS SDK DynamoDB 客户端和 DocumentClient 之间的区别?

问题描述

我想知道 AWS SDK DynamoDB 客户端和 DynamoDB DocumentClient 之间的区别?在哪个用例中我们应该使用 DynamoDB 客户端而不是 DocumentClient?

I want to know the difference between the AWS SDK DynamoDB client and the DynamoDB DocumentClient? In which use case should we use the DynamoDB client over the DocumentClient?

const dynamoClient = new AWS.DynamoDB.DocumentClient();

vs 

const dynamo = new AWS.DynamoDB();

推荐答案

我认为最好通过比较两个执行相同操作的代码示例来回答这个问题.

I think this can be best answered by comparing two code samples which do the same thing.

以下是使用 dynamoDB 客户端放置项目的方法:

Here's how you put an item using the dynamoDB client:

var params = {
    Item: {
        "AlbumTitle": {
            S: "Somewhat Famous"
        },
        "Artist": {
            S: "No One You Know"
        },
        "SongTitle": {
            S: "Call Me Today"
        }
    },
    TableName: "Music"
};
dynamodb.putItem(params, function (err, data) {
    if (err) console.log(err)
    else console.log(data);           
});

以下是使用 DocumentClient API 放置相同项目的方法:

Here's how you put the same item using the DocumentClient API:

var params = {
    Item: {
        "AlbumTitle": "Somewhat Famous",
        "Artist": "No One You Know",
        "SongTitle": "Call Me Today"
    },
    TableName: "Music"
};

var documentClient = new AWS.DynamoDB.DocumentClient();

documentClient.put(params, function (err, data) {
    if (err) console.log(err);
    else console.log(data);
});

正如您在 DocumentClient 中看到的那样，Item 以更自然的方式指定.更新 DDB 的所有其他操作(update()、delete())和从读取操作返回的项目(get()，<代码>查询()，<代码>扫描()).