How to fetch/scan all items from `AWS dynamodb` using node.js

Question

How to fetch/scan all items from AWS dynamodb using node.js. I am posting my code here.

var docClient = new aws.DynamoDB.DocumentCl         


        

Answer 1

If you would like to get the data from DynamoDB without using Hash key value, you need to use Scan API.

Note: The Scan API reads all the items in the table to get the results. So, it is a costly operation in DynamoDB.

Alternate Approach : Use 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);
        }
    }
}