Views allow users to customize the display of records by selecting specific columns to include in a grid. There are three types of views: public, system, and personal. Business rules enable client-side logic without JavaScript by setting field values, validation, visibility and other properties. Rules can show errors, set defaults, and mark fields required or editable but cannot read related entities. Both views and rules are configured through the Dynamics CRM user interface.
9. BUSINESS RULES
Client-side business logic without writing Javascript.
With Business Rules you can :-
Show an error message
Set a field value
Set a fields requirement level to Required OR Not Required
Set a fields visibility to Show or Hide
Set the Default value of a field
Set a fields Enablement level to be Editable or Locked
You can't
Read related/parent entities