Let’s say you have two domain objects/models – Feet and Toes.
Obviously, in general a Foot hasMany toes
and obviously (at least we hope) a toe belongsTo a foot.
So given this, if you, say, changed the color of the toenail on a toe, you would expect to then do a toe.save(), right?
WRONG! You get this crazy _backRef exception and you’re dead in the water.
Instead, what you have to do is save the Foot, and it cascades down and saves the toe.