导入数据时如何在Amazon dynamodb表中添加新字段？

Question

I am trying to use the new query filter feature of dynamodb. But the problem is i need to query filter on the range key attribute which .net sdk complains about "query filter only works on non-key attributes".

So i decided to add a new field to each row which has the value of range key attribute.

This:
Hash Key  | Range Key
User Id     ContentId

Will become this:
Hash Key  | Range Key  | NewField
User Id     ContentId    ContentIdForQueryFilter
1           1            1
1           2            2
1           3            3

Now i can query the table with Hash and Range Key and i can use queryfilter on ContentIdFilter because ContentIdFilter isnt a key attribute.

My question is how can i add ContentIdForQueryFilter field with the value of ContentId field on each row? Should i use Hive or Elastic Map Reduce?

How can i achieve this?

Thanks in advance.

Answer 1

If you want to query with conditions on the range key, you can set the "KeyConditions" property of your query request.

http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Query.html#DDB-Query-request-KeyConditions

Here is a java example that does a query on items with hash key equals to "id_1" and range key greater or equal to 3

    QueryRequest queryRequest = new QueryRequest();
    queryRequest.setTableName("Query");
    queryRequest.addKeyConditionsEntry("Hash", new Condition().withAttributeValueList(new AttributeValue("id_1")).withComparisonOperator(ComparisonOperator.EQ));
    queryRequest.addKeyConditionsEntry("Range", new Condition().withAttributeValueList(new AttributeValue("3")).withComparisonOperator(ComparisonOperator.GE));

    QueryResult result = dynamo.query(queryRequest);
    for(Map<String, AttributeValue> item : result.getItems()) {
        System.out.println(item);
    }

from the doc it seems key condition supports the following comparator on range key:

EQ | LE | LT | GE | GT | BEGINS_WITH | BETWEEN

is that enough for your usecase?