And what you do if in one scenario you need lazy and in another scenario you need eager fetching? Create two separate mappings and tho separate class hierarchie

And what you do if in one scenario you need lazy and in another scenario you need eager fetching? Create two separate mappings and tho separate class hierarchies to hold them? Ignore the problem and pray noone will notice it? What you do if you already closed DB transaction, and you need to access lazy collection? In my experience, this lazy/eager is the main reason I don't like rich ORM mappings. I usually don't map collections and don't map foreign keys. If I need to fetch something, I just do it. If I need to return a result of a complex query, I just define datatype for it. In general, my ORM just converts recordset to object, and that's it it, besides simple record level CRUD operations. One record operations like findByPK or deletByPK or updateByPK are fine, but for anything else I prefer writing SQL, instead of suffering with some ORM specific SQL replacement or, $deity forbid, some api. SQL is as good DSL as you can get for RDBMS access, and is fairly portable between different programming langagues and ORMs, so no reason not to use it. But many