CODEWITHSUNDEEP
amazon-web-servicesamazon-dynamodb
richs
richs

Reputation: 4769

bulk update based on dynamodb field

What is the best way to do a bulk dynamodb update based on a non-primary key field? For example if i have a table with deploymentKey = "UK" then update field config to "uk-config". I've looked the amazon documentation, specifically "update-item", but that only updates based on the primary key.

Addition I looked a java example which returns all items in a table but in my case it keeps returning no items.

// Copyright 2012-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// Licensed under the Apache License, Version 2.0.
package com.amazonaws.codesamples.document;

import java.io.IOException;
import java.util.List;
import java.util.Map;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.document.BatchGetItemOutcome;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item; 
import com.amazonaws.services.dynamodbv2.document.TableKeysAndAttributes;
import com.amazonaws.services.dynamodbv2.model.KeysAndAttributes;

public class DocumentAPIBatchGet {
    static AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard().build();
static DynamoDB dynamoDB = new DynamoDB(client);

static String forumTableName = "Forum";
static String threadTableName = "Thread";

public static void main(String[] args) throws IOException {
    retrieveMultipleItemsBatchGet();
}

private static void retrieveMultipleItemsBatchGet() {

    try {

        TableKeysAndAttributes forumTableKeysAndAttributes = new TableKeysAndAttributes(forumTableName);
        // Add a partition key
        forumTableKeysAndAttributes.addHashOnlyPrimaryKeys("Name", "Amazon S3", "Amazon DynamoDB");

        TableKeysAndAttributes threadTableKeysAndAttributes = new TableKeysAndAttributes(threadTableName);
        // Add a partition key and a sort key
        threadTableKeysAndAttributes.addHashAndRangePrimaryKeys("ForumName", "Subject", "Amazon DynamoDB",
            "DynamoDB Thread 1", "Amazon DynamoDB", "DynamoDB Thread 2", "Amazon S3", "S3 Thread 1");

        System.out.println("Making the request.");

        BatchGetItemOutcome outcome = dynamoDB.batchGetItem(forumTableKeysAndAttributes,
            threadTableKeysAndAttributes);

        Map<String, KeysAndAttributes> unprocessed = null;

        do {
            for (String tableName : outcome.getTableItems().keySet()) {
                System.out.println("Items in table " + tableName);
                List<Item> items = outcome.getTableItems().get(tableName);
                for (Item item : items) {
                    System.out.println(item.toJSONPretty());
                }
            }
            // Check for unprocessed keys which could happen if you exceed
            // provisioned
            // throughput or reach the limit on response size.
            unprocessed = outcome.getUnprocessedKeys();

            if (unprocessed.isEmpty()) {
                System.out.println("No unprocessed keys found");
            }
            else {
                System.out.println("Retrieving the unprocessed keys");
                outcome = dynamoDB.batchGetItemUnprocessed(unprocessed);
            }

        } while (!unprocessed.isEmpty());

    }
    catch (Exception e) {
        System.err.println("Failed to retrieve items.");
        System.err.println(e.getMessage());
    }
  }
}

Upvotes: 0

Views: 639

Answers (1)

maxpearl
maxpearl

Reputation: 75

DynamoDB UpdateItem only works with the partition key - if you don't know it, you can't use it. There is no way to do updates (bulk or otherwise) without the partition and the sorting key (if the table has one).

I'm not working in Java, but basically, you'll have to scan the table looking for the proper value, then update each item one by one. If you have a lot of data, it's going to be slow.

Upvotes: 1

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