Querying in DynamoDb without key condition expression

Question

I am new in DynamoDb but I want to query data using .NET and I am I little bit confused that DynamoDb forces me to use Primary key and KeyConditionExpression.

For example in SQL I can do something like this SELECT * FROM tbl1 WHERE name = 'Alex' and in this case name is NOT a primary key. But I can not do something similar in DynamoDb.

Here is my code:

        var request = new QueryRequest
        {
            TableName = "CompanyCommunication",
            KeyConditionExpression = "Id = :v_Id",
            FilterExpression = "CompanyName = :v_Com",
            ExpressionAttributeValues = new Dictionary<string, AttributeValue> {
            {":v_Com", new AttributeValue { S =  "Microsoft" }} , {":v_Id", new AttributeValue { S = "1" }  }  }
        };

Id is my primary key. But I can not comment KeyConditionExpression or use some another field in KeyConditionExpression.

But how I can do a query not using primary key? For example, using only a CompanyName field.

Maybe I misunderstand something?

Ramdev Sharma Ramdev Sharma · Accepted Answer · 2018-11-29T16:21:55

If you want to query without putting KeyCondition then you have to have Index table. You can check following link for more details.

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GSI.html

It explains with examples to use GSI.

Querying in DynamoDb without key condition expression

1 Answers