如何使用 node.js 从`AWS dynamodb` 获取扫描所有项目

如果您想在不使用散列键值的情况下从DynamoDB获取数据，则需要使用Scan API.

Note:扫描API读取表中的所有项目以获得结果.因此，在DynamoDB中，这是一项成本高昂的操作.

Alternate Approach :使用GSI

Scan Code for the above sceanario:-

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

var params = {
    TableName: "users",
    FilterExpression: "#user_status = :user_status_val",
    ExpressionAttributeNames: {
        "#user_status": "user_status",
    },
    ExpressionAttributeValues: { ":user_status_val": 'somestatus' }

};

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);
        }
    }
}