title: What's the difference between BatchGetItem and Query in DynamoDB?
body: <p>I've been going through AWS DynamoDB docs and, for the life of me, cannot figure out what's the core difference between batchGetItem() and Query(). Both retrieve items based on primary keys from tables and indexes. The only difference is in the size of the items retrieved but that doesn't seem like a ground breaking difference. Both also support conditional updates.</p>
  
  <p>In what cases should I use batchGetItem over Query and vice-versa?</p>