DataModel star schema

[#1]

in the source i have 15 sql tables from ms sql server.converted as qvds or will they chek it which fileds to  i want to create star scema.

what will do generally in organisation will they go for all tables aor will they which are useful field like only some of few fields enough will they go for apply map like functions or they load all the data and will store into qvds and then  will  they tansformations for creating starchema likthat

let me get clarified.

[#2]

Suppose apply map we apply on source Db we can do that after qvd generation as well which will be generally followed in organisations