1)How to Create User Define Role? 2)How to Give Particular Access to Role?

1) Create Read_Only Role And Give the Access of Viewing any Definition.

USE master
GO
Create role Read_Only
GRANT VIEW ANY DEFINITION TO Read_Only
USE master
GO
Revoke VIEW ANY DEFINITION TO Read_Only

2) Create Role and Give Execute Role

Create role DB_Execute
Grant Execute     to DB_Execute
Revoke Execute  to DB_Execute

3) Create Role And Give Alter Role

Create role DB_Alter
Grant Alter     to DB_Alter
Revoke Execute  to DB_Alter

4) Create Role And Give Insert,Update,Delete Role

Create Role DB_Write_Database
Grant Insert,Update,Delete to DB_Write_Database
Revoke Insert,Update,Delete to DB_Write_Database

5)If you want to Create Read-Only Definition to All DB_User expect Admin Role.

USE master
GO
GRANT VIEW ANY DEFINITION TO PUBLIC
USE master
GO
Revoke View Any Definition to Public