If you’re doing any moderately complex analysis of the data in your database, the ORM will quickly start falling down. Abstracting the query layer into the application codebase is nice, and mapping entities to objects is nice, but ORM is not a silver bullet. Learning what makes for a good schema vs a bad schema and how to avoid N+1 loading or query problems is important no matter what.

ORMs aren’t bad, but learn their escape hatches or else you’ll have a hard time doing more complicated things.