Question

我是DynamoDB的新手，我试图设计一个表并做一些概念证明。下面是我使用“本地二级索引”创建的表

var params = {
        TableName : "sample",
        KeySchema: [
            { AttributeName: "user_id", KeyType: "HASH"},
            { AttributeName: "created_date", KeyType: "RANGE"}
        ],
        AttributeDefinitions: [
            { AttributeName: "user_id", AttributeType: "S" },
            { AttributeName: "created_date", AttributeType: "S" },
            { AttributeName: "video_id", AttributeType: "S" }

        ],
        ProvisionedThroughput: {
            ReadCapacityUnits: 5,
            WriteCapacityUnits: 5
        },
        LocalSecondaryIndexes: [{
                IndexName: "user_id-video_id-Index",
                KeySchema: [
                    {
                        AttributeName: "user_id",
                        KeyType: "HASH"
                    },
                    {
                        AttributeName: "video_id",
                        KeyType: "RANGE"
                    }
                ],
                Projection: {
                    ProjectionType: "ALL"
                }
            }]

然后，我在下面插入了两个项目

项目1：

{
    "company": "comapnyname",
    "created_date": "02-28-2019",
    "email": "randomguy@abc.com",
    "first_name": "John",
    "last_name": "Doe",
    "profile_pic": "https://s3location",
    "user_id": "vshdhfb"
  }

项目2：

{
                "author": "Phil DiMaggio",
                "created_date": "02-29-2018",
                "description": "This video further introduces the Business Sales compensation plans.",
                "likes": "12",
                "title": "Understanding Business Sales Compensation Plans",
                "user_id": "vshdhfb",
                "video_id": "vdhk23so9",
                "video_loc": "https://s3.amazonaws.com/videos/video.mp4",
                "views": "45"
              }

然后，我尝试使用以下代码更新/删除第二项，它给我一个错误，显示为“消息”：“所需键之一未提供值”

var params = {
        TableName: "sample",

        Key:{
            "video_id": "vdhk23so9",
            "user_id":"vshdhfb"
        },
        UpdateExpression: "set likes = likes + :val",
        ExpressionAttributeValues:{
        ":val":1
        },
        ReturnValues:"UPDATED_NEW"
    };

    docClient.update(params, function(err, data) {
        if (err) {
            document.getElementById('textarea').innerHTML = "Unable to update like: " + "\n" + JSON.stringify(err, undefined, 2);
        } else {
            document.getElementById('textarea').innerHTML = "Like video succeeded: " + "\n" + JSON.stringify(data, undefined, 2);
        }
    });
}

我需要添加另一个密钥吗？我想念什么？

Answer 1

您的第三个代码块未提供create_date的值。此字段定义为键的一部分：

    TableName : "sample",
    KeySchema: [
        { AttributeName: "user_id", KeyType: "HASH"},
        { AttributeName: "created_date", KeyType: "RANGE"}

您必须同时提供user_id和created_date才能唯一标识一条记录。

哦，可能不会引起问题，但这是无效的日期，因为2018年不是a年：

"created_date": "02-29-2018",

日期以字符串形式存储，因此不会引起错误，但是您也可以考虑以更有用的格式存储日期，例如YYYY-MM-DD，这样可以更轻松地进行排序并避免与美国日期格式（例如01-02-2019是2月1日还是1月2日？）。

必需的键之一未提供值-AWS

1 个答案: