Seven Databases in Seven Weeks, 2nd Edition

Day 1: Let’s Go Shopping!

Fun fact: Dynamo—the database that inspired the later DynamoDB—was originally built with the very specific purpose of serving as the storage system for Amazon’s famous shopping cart. When you’re building a shopping cart application, the absolute, unbreakable categorical imperative guiding your database should be this: do not lose data under any circumstances. Losing shopping cart data means losing money directly. If a user puts a $2,500 mattress in their Amazon shopping cart and the database suddenly forgets that, then that’s money potentially lost, especially if the data is lost just before checkout.

Multiply a mistake like that times thousands or even millions and you get a clear sense of why Amazon needed to build ...