AWS开发工具包DynamoDB客户端和DocumentClient之间的区别？ [英] Difference between AWS SDK DynamoDB client and DocumentClient?

问题描述

我想知道AWS开发工具包DynamoDB客户端和DynamoDB DocumentClient之间的区别吗？在哪种用例中，我们应该在DocumentClient上使用DynamoDB客户端？

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

我认为这是最好的答案通过比较两个做相同事情的代码示例。

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

这是使用dynamoDB客户端放置项目的方式：

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放置同一项目的方法：

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);
});

在 DocumentClient 中可以看到 Item 以更自然的方式指定。在所有其他更新DDB的操作（ update（）， delete（））和返回的项目中也存在类似的区别从读取操作（ get（）， query（）， scan（））。

As you can see in the DocumentClient the Item is specified in a more natural way. Similar differences exist in all other operations that update DDB (update(), delete()) and in the items returned from read operations (get(), query(), scan()).

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