node.js - 使用 Node.js 更新表达式时出现 dynamo 数据库错误

Question

我需要更新我的 aws-dynamo 数据库上的列表。我创建了一个带有分区键的表:电子邮件。然后我成功地将一些电子邮件 ID 插入到表中。现在我的 table 是这样的

电子邮件

manaf1@gmail.com

manaf2@gmail.com

manaf3@gmail.com

然后，我尝试使用新键“details”更新表，其值是一个列表。这是我的代码

var AWS = require("aws-sdk");

var params =
    {
        TableName: "manaftable1",
        Key: { email: "manaf1@gmail.com" },
        UpdateExpression: "set #details = list_append (#details, :detailsinput)",
        ExpressionAttributeNames: {
            "#details": "details"
        },
        ExpressionAttributeValues: {
            ":detailsinput":{ "id": "1","mob": "978956" }
        }
    };


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

docClient.update(params, function (err, data) {
    if (err)
        console.log(JSON.stringify(err, null, 2));
    else
        console.log(JSON.stringify(data, null, 2));
});

但是我遇到了这样的错误

{
  "message": "Invalid UpdateExpression: Incorrect operand type for operator or function; operator or function: list_append, operand type: M",
  "code": "ValidationException",
  "time": "2016-10-26T11:04:60.756",
  "requestId": "SN0NPRHDFHUKBBJHOVI0DFHHRQNSO5AEMVJFFGHF9ASFHUAAJG",
  "statusCode": 400,
  "retryable": false,
  "retryDelay": 0
}

更新后我需要这样的回复

第 1 列:电子邮件

第2列:详细信息

manaf1@gmail.com | [{"id":"1","mob":"978956"},{"id":"2","mob":"767886"}]

manaf2@gmail.com |

与我的代码相关的问题是什么？

Answer 1

作为 list_append says 的 AWS 文档:

The new element must be contained in a list, for example to add 2 to a list, the operand would be [2]

因此您需要附加一个对象数组，而不仅仅是一个对象:

var params =
    {
        TableName: "manaftable1",
        Key: { email: "manaf1@gmail.com" },
        UpdateExpression: "set #details = list_append (#details, :detailsinput)",
        ExpressionAttributeNames: {
            "#details": "details"
        },
        ExpressionAttributeValues: {
            ":detailsinput": [{ "id": "1","mob": "978956" }]
        }
    };

如果对象中不存在该属性，可以使用if_not_exists操作数:

var params =
    {
        TableName: "manaftable1",
        Key: { email: "manaf1@gmail.com" },
        UpdateExpression: "set if_not_exists(#details, []) set #details = list_append (#details, :detailsinput)",
        ExpressionAttributeNames: {
            "#details": "details"
        },
        ExpressionAttributeValues: {
            ":detailsinput": [{ "id": "1","mob": "978956" }]
        }
    };