node.js - 动态模块 : query with hash key only

Question

我有这张表:

• DomainId 字符串 HashKey
• EmailId 字符串 RangeKey

我想知道是否可以仅使用 HashKey 查询此表，如下所示:

var AWS = require("aws-sdk");   
var client = new AWS.DynamoDB.DocumentClient();
var dm = 'infodinamica.cl';

//Set params
var params = {
    TableName : 'table-name',
    KeyConditionExpression: "DomainId = :dm",       
    ExpressionAttributeValues: {
        ":dm": dm
    },
    Select: 'COUNT'
};

client.query(params, (err, data) => {
    if(err)
        console.log(JSON.stringify(err, null, 2));
    else
        console.log(JSON.stringify(data, null, 2));
}

ps:注意这张表有HashKey和RangeKey。

Answer 1

是的，仅使用 query API 就可以使用 Hash Key 查询数据。

Use the KeyConditionExpression parameter to provide a specific value for the partition key. The Query operation will return all of the items from the table or index with that partition key value. You can optionally narrow the scope of the Query operation by specifying a sort key value and a comparison operator in KeyConditionExpression. You can use the ScanIndexForward parameter to get results in forward or reverse order, by sort key.