is it good for select component' parameter t:model not null

I feel that it is not so good that select's parameter model not allow null. because when render, i get the model from Database, when submit i have already selected value, so why i have to get the model again. the performance is a problem. i just want the selected value to do some work.

is it good for select component' parameter t:model not null

I feel that it is not so good that select's parameter model not allow null.