[ehutch79]

That doesn't sound like a good ORM. They should be lazy until you access the relevant data.

That said.

This is where the knowing what's going on behind the scenes matters.

[ryanbrunner]

Oh they would be lazy, it's just that expressing something like that efficiently (i.e. something like "SELECT foo.*, (SELECT count(1) FROM bar where foo_id = foo.id") is usually really hard to do. Most ORMs I've seen would N+1 on that with a naive approach, and even the "optimized" approach will want to fetch all bars vs. just the counts.