NOT_NULL query condition on globalSecondaryIndex in dynamodb query

Question

Is it possible to add constraint to a dynamodb query expression that states that a GSI should be not null?

Can somebody provide examples.

Is possible to construct a query like the one below?

new DynamoDBQueryExpression<XXX>()
            .withHashKeyValues(YYY).withKeyConditionExpression(GSI != NULL);

Note: Please let me know if this is possible in during query and not during filter time?

What do you mean when you say GSI null? attributes or hash/range keys? — Harshal Bulsara, Aug 24 '16 at 07:06
Could you please provide the sample data? I would like to check whether you meant GSI attribute exist and doesn't have any value and how it is stored in the DynamoDB table? — notionquest, Aug 24 '16 at 08:47

score 1 · Answer 1 · answered Jun 03 '19 at 13:46

1

if you're like me and you landed on this page while finding the answer to the above question, here's the thread you need to see

How do you query for a non-existent (null) attribute in DynamoDB

answered Jun 03 '19 at 13:46

Kehinde Adedamola Shittu

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score 0 · Answer 2 · answered Aug 24 '16 at 12:20

The DynamoDB String attribute can't have NULL or empty string.

When you try to insert NULL, the API should throw the below exception:-

java.lang.IllegalArgumentException: Input value must not be null

When you try to insert empty string, the API should throw the below exception:-

com.amazonaws.AmazonServiceException: One or more parameter values were invalid: An AttributeValue may not contain an empty string

If you want to add additional filters on some attributes (i.e. attributes other than hash or range key), you can use the below syntax (i.e. withFilterExpression).

Not equals operator is "<>"

Map<String, AttributeValue> eav = new HashMap<String, AttributeValue>();
eav.put(":val1", new AttributeValue().withS("Some value"));

DynamoDBQueryExpression<XXX> queryExpression = new DynamoDBQueryExpression<XXX>();
    queryExpression.withHashKeyValues(hashKeyValues);       
    queryExpression.withFilterExpression("docType <> :val1").withExpressionAttributeValues(eav);

NOT_NULL query condition on globalSecondaryIndex in dynamodb query

2 Answers2