DynamoDB GetItemResult GetItem用于多个项目

Question

As I understand it, the return value for GetItem is Map<String,AttributeValue> . This is a map of attribute name to attribute value for a single item, a row, in the DB.

What if the hash and range values don't result in an unique result? Does the SDK throw an exception or something? My table is set up so that with hash and range attributes I set I will generally not get unique results.

I understand I can do a query and get multiple items back, but it is more expensive and slower?

Answer 1

The composite key hash + range should result in unique result only.
If you have a table with both hash and range key then dynamo db will override the previous value of the row with the same hash and range value.

So this is not possible -->

My table is set up so that with hash and range attributes I set I will generally not get unique results.