title: What is the point in validating data in SQL-based DBs while it should be validated once the API recieves it?
body: <p>Any API should validate the data once it recieves it, so if there is some invalid data the API will take an action before processing anything.<br />
  As of my understanding, SQL-based databases validate data once again according to some constraints.<br />
  Doesn't this cost more performance or am I not understanding correctly ?</p>