title: Add an attribute to every item in a DynamoDB table with millions of items
body: <p>I am pretty new to AWS, but I need to add an attribute (and set the value to something) to every single item in a DynamoDB table. </p>
  
  <p>I'm trying to write a generic script that will be able to do this to any table passed into it. </p>
  
  <p>After a little bit of digging, it looks like I should be able to do this just by doing a scan of the table, getting the items, and then updating every single item. </p>
  
  <p>My questions are:
  (1) Does this seem like a reasonable approach?
  (2) Is there an easier / better way to do this automatically? (a table-wide addition of an attribute to every item in the table?)</p>