CODEWITHSUNDEEP
amazon-web-servicesamazon-dynamodb
user2924127
user2924127

Reputation: 6252

How to update item by Composite Primary Key in Dynamodb

I have a table called friends:

Friend 1 | Friend 2 | Status

Friend 1 is my HASH attribute and Friend 2 is my range attribute.

I would like to update an item's staus attribute where friend 1 = 'Bob' and friend 2 = 'Joe'. Reading through the documentation on http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/JavaDocumentAPICRUDExample.html I can only see how to update an item by 1 key, how do I include the other key?

Upvotes: 0

Views: 3414

Answers (3)

Garret Wilson
Garret Wilson

Reputation: 21386

I believe the question is using the AWS Java SDK 1.x. If you consider switching to the SDK 2.x, the DynamoDB documentation has an example for updating an item which shows setting up a map with the key:

HashMap<String,AttributeValue> itemKey = new HashMap<>();
itemKey.put(key, AttributeValue.builder()
    .s(keyVal)
    .build());

If you have a composite key, just add both key attributes to the map:

HashMap<String,AttributeValue> itemKey = new HashMap<>();
itemKey.put(partitionKey, AttributeValue.builder()
    .s(partitionKeyVal)
    .build());
itemKey.put(sortKey, AttributeValue.builder()
    .s(sortKeyVal)
    .build());

This map is later passed to the update request exactly as is shown in the example on that page:

UpdateItemRequest request = UpdateItemRequest.builder()
    .tableName(tableName)
    .key(itemKey)
    .attributeUpdates(updatedValues)
    .build();

As a side note, the online example currently uses:

HashMap<String,AttributeValue> itemKey = new HashMap<>();

That is bad practice; you should program to interfaces. Thus the better code would be:

Map<String,AttributeValue> itemKey = new HashMap<>();

If you're using Java 9+, you can use Map.of(…) to create the map in one statement rather than having separate put(…) commands. Whether you use Map.of(…) is a matter of preference.

Upvotes: 0

Nick
Nick

Reputation: 783

Here you go:

DynamoDBQueryExpression<Reply> queryExpression = new DynamoDBQueryExpression<Reply>()
            .withKeyConditionExpression("Id = :val1 and ReplyDateTime > :val2")
            .withExpressionAttributeValues(
...

where Id is the Hash Key and ReplyDateTime is the Range Key.

Reference: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBMapper.QueryScanExample.html

Upvotes: 0

Yanish Pradhananga
Yanish Pradhananga

Reputation: 755

I'm writing example where you can make update of multiple item in single table. I have primary key as id and range key as Datetime. Actually there is no feature available in dynamodb so what i'm doing here is first query all the variable with hash key and range key of which i want to make update. Once all data are stored in List then loading data with it's hash key and rangekey and changing or updating field using set and save it. Since I'm editing in hash key so, hash key original will be there we need to delete it. If you need to update in next attribute no need. I haven't added deleting code write yourself. You can query if you have confusion your entry with hash key will be still and new entry with new hash key will be added. Code is below:

public static void main(String[] args) {
    AmazonDynamoDBClient client = new AmazonDynamoDBClient();
    DynamoDBMapper mapper = new DynamoDBMapper(client);
    client.setEndpoint("http://localhost:8000/");
    String fromDate = "2016-01-13";
    String toDate = "2016-02-05";
    User user = new User();
    user.setId("YourHashKey");
    LocalDate frmdate = LocalDate.parse(fromDate, DateTimeFormatter.ISO_LOCAL_DATE);
    LocalDate todate = LocalDate.parse(toDate, DateTimeFormatter.ISO_LOCAL_DATE);
    LocalDateTime startfrm = frmdate.atStartOfDay();
    LocalDateTime endto = todate.atTime(23, 59, 59);
    Condition rangeCondition = new Condition().withComparisonOperator(ComparisonOperator.BETWEEN.toString()).withAttributeValueList(new AttributeValue().withS(startfrm.toString()), new AttributeValue().withS(endto.toString()));
    DynamoDBQueryExpression<User> queryExpression = new DynamoDBQueryExpression<User>().withHashKeyValues(user).withRangeKeyCondition("DATETIME", rangeCondition);
    List<User> latestReplies = mapper.query(User.class, queryExpression);
    for (User in : latestReplies) {
        System.out.println(" Hashid: " + in.getId() + " DateTime: " + in.getDATETIME() + "location:" + in.getLOCID());
        User ma = mapper.load(User.class, in.getId(), in.getDATETIME());
        ma.setLOCID("Ohelig");
        mapper.save(ma);
    }
}

Upvotes: 0

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