Industry standard in DAL datasets?

Question

Hi,
In my DAL there are classes to authenticate users and to perform CRUD operations.
Assume there are two main fucntions as mentioned user Authentication and CRUD operations, i could automate CRUD operations from wizard and for this i have to create a dataset that may have two or three tables. Authenticate is another fuction.. for this i need to another table.....
Do i need to create a Dataset in it should i implement my Database with all relationships?
Or
Should i create two datasets one ONLY to perform user authentication and another to do all CRUD operations?
TY