Your database is often the most important part of your application in terms of actual value to the business. The value of the database will only increase over time, as long as it is adequately maintained. Your database administrator is in charge of this maintenance, and you’ll often find that the constraints under which they are operating are very different than yours.
Typically an ORM integrates a unit of work pattern that allows you to modify multiple objects then push the changes back to the database as a unit. This returns a chunk of data known as an aggregate root. The ORM pulls the data from the database and allows the developer to edit the data as an object in the code then returns it to the database. The ORM figures out what SQL to generate to send the data back to the database. This is called a unit of work pattern. It is effectively a transaction as it either all goes to the database or none.