InvalidParameterType: params.ExpressionAttributeValues[':et1'].N应为字符串

Question

下面是我用来进行查询的代码：

var scanParams = {
        TableName : 'xxxx',
        FilterExpression : '( (event = :e0) AND (event = :e1 AND eventTime > :et1 AND eventTime < :et2) )',
        ExpressionAttributeValues: { 
          ':e0': { S: 'ME 21' },
          ':e1': { S: 'ME 21' },
          ':et1': { N: 1509267218 },
          ':et2': { N: 1509353618 } 
        },
        ProjectionExpression: "event, customer_id, visitor",
    };

在相应的dynamodb表的配置中，我似乎为eventTime列添加了Nummber。

​

​

下面是错误：

error happened  { MultipleValidationErrors: There were 2 validation errors:
* InvalidParameterType: Expected params.ExpressionAttributeValues[':et1'].N to be a string
* InvalidParameterType: Expected params.ExpressionAttributeValues[':et2'].N to be a string
    at ParamValidator.validate (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/param_validator.js:40:28)
    at Request.VALIDATE_PARAMETERS (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/event_listeners.js:125:42)
    at Request.callListeners (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/sequential_executor.js:105:20)
    at callNextListener (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/sequential_executor.js:95:12)
    at /home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/event_listeners.js:85:9
    at finish (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/config.js:315:7)
    at /home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/config.js:333:9
    at SharedIniFileCredentials.get (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/credentials.js:126:7)
    at getAsyncCredentials (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/config.js:327:24)
    at Config.getCredentials (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/config.js:347:9)
    at Request.VALIDATE_CREDENTIALS (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/event_listeners.js:80:26)
    at Request.callListeners (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/sequential_executor.js:101:18)
    at Request.emit (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/sequential_executor.js:77:10)
    at Request.emit (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/request.js:683:14)
    at Request.transition (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/request.js:22:10)
    at AcceptorStateMachine.runTo (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/state_machine.js:14:12)
    at Request.runTo (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/request.js:403:15)
    at /home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/request.js:791:12
    at Request.promise (/home/jahidul/workspace/backstage-opticon/node_modules/aws-sdk/lib/request.js:777:12)
    at DynamoDBService.scanItem (/home/jahidul/workspace/backstage-opticon/shared/services/dynamodb/dynamodb.service.ts:52:39)
    at /home/jahidul/workspace/backstage-opticon/job-scripts/dyno-test.js:57:12
    at sailsReady (/home/jahidul/workspace/backstage-opticon/node_modules/sails/lib/app/lift.js:49:12)
    at /home/jahidul/workspace/backstage-opticon/node_modules/async/lib/async.js:251:17
    at /home/jahidul/workspace/backstage-opticon/node_modules/async/lib/async.js:154:25
    at /home/jahidul/workspace/backstage-opticon/node_modules/async/lib/async.js:248:21
    at /home/jahidul/workspace/backstage-opticon/node_modules/async/lib/async.js:612:34

有什么想法吗？提前谢谢。

Answer 1

使用下面的参数：

var scanParams = {
        TableName : 'xxxx',
        FilterExpression : '( (event = :e0) AND (event = :e1 AND eventTime > :et1 AND eventTime < :et2) )',
        ExpressionAttributeValues: { 
          ':e0': { "S": "ME 21" },
          ':e1': { "S": "ME 21" },
          ':et1': { "N": "1509267218" },
          ':et2': { "N": "1509353618" } 
        },
        ProjectionExpression: "event, customer_id, visitor",
    };

在Dynamo DB中，类型(Number)由"N“表示，值必须为字符串格式"1509353618”。希望这能解决你的问题。

Answer 2

实际上，您不需要包含et1和et2变量的数据类型。DynamoDB应用程序接口应该能够自动将其解释为数字。类似地，对于变量e0和e1。

请尝试下面的代码。

var scanParams = {
        TableName : 'xxxx',
        FilterExpression : '( (event = :e0) AND (event = :e1 AND eventTime > :et1 AND eventTime < :et2) )',
        ExpressionAttributeValues: { 
          ':e0': 'ME 21',
          ':e1': 'ME 21',
          ':et1': 1509267218,
          ':et2': 1509353618
        },
        ProjectionExpression: "event, customer_id, visitor",
    };

完全测试代码：-

您可能需要在以下代码中更改表名和键属性名称。

var AWS = require("aws-sdk");
var creds = new AWS.Credentials('akid', 'secret', 'session');

AWS.config.update({
    region: "us-west-2",
    endpoint: "http://localhost:8000",
    credentials: creds
});

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

var params = {
    TableName: "table4",
    FilterExpression: "userid = :user_id1 AND (userid = :user_id2 AND ts > :et1 AND ts < :et2)",
    ExpressionAttributeValues: { ":user_id1": 'ME 21',
        ":user_id2": 'ME 21',
        ":et1" : '1509267216',
        ":et2" : 1509353618,
    }

};

docClient.scan(params, onScan);
var count = 0;

function onScan(err, data) {
    if (err) {
        console.error("Unable to scan the table. Error JSON:", JSON.stringify(err, null, 2));
    } else {
        console.log("Scan succeeded.");
        data.Items.forEach(function (itemdata) {
            console.log("Item :", ++count, JSON.stringify(itemdata));
        });

        // continue scanning if we have more items
        if (typeof data.LastEvaluatedKey != "undefined") {
            console.log("Scanning for more...");
            params.ExclusiveStartKey = data.LastEvaluatedKey;
            docClient.scan(params, onScan);
        }
    }
}