DynamoDb Multiple Conditional Updates of Non-dependant Attributes

Question

I am using the Javascript SDK for AWS and I am attempting to perform a single update operation on OHLC (Open, High, Low, Close) data and I only want to update the "High" attribute if the new value is higher than the stored value and the opposite for the "Low".

As far as I can tell, there are 2 options:

1. Query the dB to get the current OHLC, calculate the differences, then update the dB again.
2. Perform 2 updates, one with the conditional expression for "High" and one for the "Low" conditional expression.

The basis of the question is this: "Can I use the conditionExpression to perform multiple, non-dependant update conditions on seperate attributes?"

Answer 1

I'm afraid its not possible to have 2 non-dependent conditions on the same UpdateItem API call.

Your first options is more cost effective, however, you may need to use versioning if you have high concurrency.