DynamoDB Conditional Checks on Arrays of Strings

Question

Can I check if part of an element exists in an Array of Strings, or check if multiple elements exist in one query? So:

1) Does an element start with 'aaa:' in the array ['aaa:1', 'bab:0', 'aab:1']

2) Does the element 'aaa:1' OR 'aaa:0' exist in the array ['aaa:1', 'bab:0','aab:1']

If so, do not execute the API operation.

Is this possible? The Documentation isn't clear if UPDATE_ITEM is this robust or not.

Answer 1

The short answer is: NO for both

The long answer is:

• Point 1) will never be possible
• Point 2) can be done using the CONTAINS filter of the scan operation but... only for a single match. No "OR" stuff. However, scan is both slow and expensive and thus heavily discouraged.

UPDATE_ITEM conditions will only allow exact matches.