javascript - DynamoDB 查询错误 : Multiple Validation Error

Question

嗨，我真的不知道如何解决这个问题。在 Lambda 中测试时，我不断收到多个验证错误。我四处搜寻，有人说要更新到最新的 SDK，我也这样做了，但仍然收到相同的错误。我尝试在 new AWS.DynamoDB.DocumentClient(); 中使用其他 api但这只是在我的日志中返回未定义。如何获取我的代码以从 DynamoDB 进行查询？

'use strict';

var APP_ID = "amzn1.echo-sdk-ams.app.ca7e2a16-1bf9-4b5b-8a7e-8c15fb0ccd9d";


var AlexaSkill = require('./AlexaSkill');



var SatTracker = function () {
    AlexaSkill.call(this, APP_ID);
};
var AWS = require('aws-sdk');
AWS.config.update({region: 'us-east-1'});
var doc = require("dynamodb-doc");

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

function getZipcode(zipcode) {

    var queryParams = {
        TableName : "ZipcodeUSA",
        KeyConditionExpression: "#zc = :zip",
        ExpressionAttributeNames:{
            "#zc": "zipcode"
        },
        ExpressionAttributeValues:{
            ":zip":zipcode
        }
    };    
    console.log("about to start dynamoDB query with zipcode: " + zipcode); 
    dynamodb.query(queryParams, function(err, data) {
        if (err) {
            console.log("error in dynamo.query of getZipcode funtion: " + err);
        } else {
        var zipData;
        console.log("starting dynamoDB query with zipcode: " + zipcode); 
        if (data && data.Items && data.Items.length > 0) {
            console.log("Found " + data.Items.length + " matching zipcode");
            if (data.Items.length === 1) {
                zipData = data.Items[0];
                return zipData;
            }
        }


        }
         console.log("completed dynamo.query with zipcode: " + err);
    });    
}

Answer 1

确保传递给 ExpressionAttributeValues 的邮政编码实际上是一个对象。假设邮政编码是一个字符串，它应该如下所示:

var queryParams = {
    TableName : "ZipcodeUSA",
    KeyConditionExpression: "#zc = :zip",
    ExpressionAttributeNames:{
        "#zc": "zipcode"
     },
     ExpressionAttributeValues:{
         ":zip": { "S" : zipcode } // S if your zip code is a String N if its a number
      }
};    

希望这有帮助