使用java sdk从具有散列范围模式的给定散列键中查询DynamoDB中的所有项

Question

EDIT: I was actually incorrect. I was querying the table when I meant to query an index which explains my error. Vikdor's solution is a valid one though.

ORIGINAL: I have a table with a Hash-Range key schema in DynamoDB. I need to be able to get all items associated with a specific hash key but it seems to require a range key condition. My issue is I want EVERY range key but there is no wildcard option. As of right now my range key is a string and the only way I could think to do this is by querying all range keys greater or equal to the smallest ascii characters I can use since the documentation says it sorts based on ascii character values.

I looked into scanning but it appears that simply will read the entire table which is NOT an option.

Is there any better way to query for all values of a hash key or can anyone confirm that using the method with the ascii character will work?

Answer 1

but it seems to require a range key condition.

This doesn't sound to be true.

I use DynamoDBMapper and use DynamoDBQueryExpression to query all the records with a given HashKey as follows:

DynamoDBQueryExpression<DomainObject> query = 
    new DynamoDBQueryExpression<DomainObject>();
DomainObject hashKeyValues = new DomainObject();
hashKeyValues.setHashKey(hashKeyValue);
query.setHashKeyValues(hashKeyValues);
// getMapper() returns a DynamoDBMapper object with the appropriate 
// AmazonDynamoDBClient object.
List<DomainObject> results = getMapper().query(query);

HTH.

Answer 2

You can use DynamoDB's query API, which allows you to query the database based conditional expressions using the hash/range keys. You can see examples of the API here . Here is a relevant example:

ItemCollection<QueryOutcome> items = table.query("theHashFieldName", "theHashFieldToQuery");

You can also query using more complex expressions. Eg:

DynamoDB dynamoDB = new DynamoDB(
    new AmazonDynamoDBClient(new ProfileCredentialsProvider()));

Table table = dynamoDB.getTable("TableName");

QuerySpec spec = new QuerySpec()
    .withKeyConditionExpression("Id = :v_id")
    .withValueMap(new ValueMap()
        .withString(":v_id", "TheId"));

ItemCollection<QueryOutcome> items = table.query(spec);

Iterator<Item> iterator = items.iterator();
Item item = null;
while (iterator.hasNext()) {
    item = iterator.next();
    System.out.println(item.toJSONPretty());
}