DyanmoDB query to fetch item using non partition key

Question

I have requirement to fetch the item from dynamodb based on the order id(not the partition key).

If the order id is 123456 as mentioned the in the above example I should get this item.

Can somebody please let me know if it is possible to achieve this. If yes, how?

DynamoDB Table

@DynamoDBTable(tableName="SomeTable")
public class SomeTable {
private String id;
private String name;
private List<Order> orders;

 @DynamoDBHashKey(attributeName="id")
    public String getId() {
        return id;
    }


}

Class 2

@DynamoDBDocument
public class Order {
private String id;
private String name;
}

DynamoDB Table Data

 "Items": [
     {
         "orders": {
             "L": [
                 {
                     "M": {
                         "name": {
                             "S": "xyz"
                         },
                         "id": {
                             "S": "123456"
                         }
                     }
                 }
             ]
         },
         "id": {
             "S": "789"
         },
         "name": {
             "S": "abcd"
         }
     }

F_SO_K · Accepted Answer · 2018-08-09 07:39:08Z

0

Do a Scan not a Query https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html

When you do the scan your AttributeValue needs to be a String Set, not just a String.

In your FilterExpression use the condition CONTAINS with your AttributeValue https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Condition.html

answered Aug 9, 2018 at 7:39

F_SO_K

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2 Comments

prevmware Over a year ago

Map<String, AttributeValue> map = new HashMap<>(); 		map.put("name", new AttributeValue().withS("xyz")); 		map.put("id", new AttributeValue().withS("123456")); 		 		Map<String, AttributeValue> eav2 = new HashMap<>(); 		eav2.put(":orders", new AttributeValue().withM(map)); 		DynamoDBScanExpression scanExpression = new DynamoDBScanExpression() 				.withFilterExpression("contains (orders, :orders)") 				.withExpressionAttributeValues(eav2 );  		List<SomeTable > list= mapper.parallelScan(SomeTable .class, 				scanExpression, 1);

prevmware Over a year ago

This above code works but I have to pass whole map but in my case I can't pass whole map, I will have only id and not the name. Is there any way I can achieve this?

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