Java Programming

Hello,

I have a question regarding storing database values in a list or any other collection object.

I have a datatable (jsf) and records are populated from database at the time of loading a page.
User has the option to change the values in the page and based on this records should change.

So is this a good idea to fire a SQL to get the data based on user's selection in the page or fetch all db values at the time of loading
and store in a collection object (one time) ?

if I am storing in a list or collection object, how can I get the values of list or collection object based on user's selection like we put where condition in sql statement?

Any help is highly appreciable.

Thanks