How to update only part of the JSON? - amazon-dynamodb

Question

I have a DynamoDB table:
+--------------------------------------------------+
| Customer ID (Primary Key)|Gamestats (JSON entry) |
+--------------------------------------------------+
JSON:
{
"Gamestats": [
{
"ID": "QuickShootingMode",
"status": 1
},
{
"ID": "FastReloadMode", // Just want to update this and not update the entire JSON
"status": 0
}
],
"CustomerID": "xyz"
}
I want to update only parts of the JSON. What is the best way to do it? Eg, update the QuickShootingMode to be false.
One way is to make a call and fetch the JSON and then Iterate the JSON and update the value and then put the new JSON back in dynamo DB. It means it would make 2 calls
A) to get the data and
B) to put the data in DB.
Is there a better way by which I could directly update the data and avoid making these extra network calls? I could convert each key of the JSON to be a column in dynamo BD, but if the number of keys grows then I’ll end up having lots of column (which might be a bad design), hence I think having the JSON saved in one column Game stats would make more sense.
Map<String, AttributeValue> key = new HashMap<>();
AmazonDynamoDB dynamoDB = dynamoDBClient.getDynamoDB();
key.put(USER_ID_KEY, new AttributeValue().withS("xyz"));
key.put("Gamedata", new AttributeValue().withS("some JSON"));
PutItemRequest request = new PutItemRequest()
.withTableName(table)
.withItem(key);
PutItemResult result = dynamoDB.putItem(request);
Is there a better way to achieve what I want?

Answer 1

It looks like from your question you are storing stringified JSON. If so an update won't help you, but as far as I can tell there is no value in storing stringified JSON instead of using dynamodb maps and lists.
You can use an update to set a nested attribute in a map or a list. Using a map instead of a list for the gamestats attribute is better because then you don't have to worry about the order of the attributes.
Javascript example with Gamestats being a map.
dynamodb.update({
TableName: table,
Key: key,
UpdateExpression: 'SET #gs.#qs.#status = :newStatus',
ExpressionAttributeNames: {'#gs': 'Gamestats', '#qs': 'QuickShootingMode', '#status': 'status' },
ExpressionAttributeValues: { ':newStatus': false }
}, callback)