node.js – 如何使用AWS Lambda按名称查询dynamoDB表

表名xx

主分区键ID(数字)

主排序键名称(String)

我想通过名字查询它.

'use strict';
const AWS = require("aws-sdk");
const dynamodb = new AWS.DynamoDB();
const docClient = new AWS.DynamoDB.DocumentClient();

exports.handler = function(event, ctx, callback) {

    var params = {
          TableName: 'xx',

            KeyConditionExpression: "#name = :name",
                 ExpressionAttributeNames:{
            "#name": "name"
        },
                     ExpressionAttributeValues: {
            ":name":event.name
        }
    };

    docClient.query(params, function(err, data){
        if(err){
            callback(err, null);
        }else{
            callback(null, data);
        }
    });
}

但我得到一个错误称：“查询条件错过了关键架构元素：id：”如何处理？

>创建全局二级索引并对其进行查询(Link)：

“A global secondary index contains a selection of attributes from the base table, but they are organized by a primary key that is different from that of the table. The index key does not need to have any of the key attributes from the table; it doesn’t even need to have the same key schema as a table.”

>扫描而不是查询：

var params=  {
    TableName:'xx',
    ProjectionExpression:'name', // remove this string if you want to get not only 'name'
    FilterExpression:'name = :name',
    ExpressionAttributeValues:{ ":name" : event.name }
};

docClient.scan(params, function(err, data){
    if(err){
        callback(err, null);
    }else{
        callback(null, data);
   }
});

如果您的表格不会很大,那么扫描是更容易和更便宜的方式(我认为全球中学指数有相关成本),但“正确”的方法是使用全球二级指数.