Ravi Sir's Cards › AWS
Conditional writes
What is a VPC: your own private network inside one AWS Region, example ThreeTierVpc 10.0.0.0/16.
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What this card says
Why do we need it?
Only one booking may win.
What is it?
attribute_not_exists(pk).
How to do it
Lost race: ConditionalCheckFailed.
Example
Counters: ADD hits :one.