Question

我的用例

我有一个表名Test，分区键为userId，排序键为campaignId。我的桌子看起来像这样

"userId (S)","noteId (S)","BName (S)","BValue (S)"
"123_x","123","hi","no"
"123_x","213","how","yes"
"123_x","321","are","yes"
"456_y","456","you","yes"
"456_y","546","i","yes"
"456_y","654","have","yes

现在，我正在尝试检索包含分区键x的项目。为此，我使用了下面的node.js代码

var AWS = require("aws-sdk");
AWS.config.update({
 region: "ap-south-1",
 endpoint: "http://dynamodb.ap-south-1.amazonaws.com"
});

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

var params = {
    TableName : "Test",
    ProjectionExpression:"userId,BName,BValue",
    KeyConditionExpression: "contains(#userId,:userid)",
    ExpressionAttributeNames:{
        "#userId": "userId"
        },
    ExpressionAttributeValues: {
        ":userid": "x"
    }
};

docClient.query(params, function(err, data) {
    if (err) {
        console.log("Unable to query. Error:", JSON.stringify(err, null, 2));
    } else {
        console.log("Query succeeded.");
        data.Items.forEach(function(item) {
            console.log(JSON.stringify(item));
        });
    }
});

我遇到这样的错误：

Unable to query. Error: {
  "message": "Invalid operator used in KeyConditionExpression: contains",
  "code": "ValidationException",
  "time": "2018-08-23T17:59:01.094Z",
  "requestId": "O6PL6NSE1BR7QLGA4U1SOIKGJ7VV4KQNSO5AEMVJF66Q9ASUAAJG",
  "statusCode": 400,
  "retryable": false,
  "retryDelay": 34.77326742946143
}

似乎我不能在关键条件表达式中使用包含。解决方法是什么？

感谢您的帮助

谢谢

Answer 1

没有一个。执行DynamoDB查询时，您必须始终指定确切的分区键。在不重新设计表的情况下，您唯一的选择是执行扫描并在userId上使用过滤器表达式。

为了避免进行表扫描，请在表上添加一个名为“ userId_suffix”的字段，并使用示例中的“ x”和“ y”类型值填充该字段。然后，您将在“ userId_suffix”上创建一个全局二级索引，并在其上查询“ x”。

是否要检索特定分区键结构上的结果？

1 个答案: