Roles and privileges will define what (in this case) a newly created ‘user-login’ can do.
GRANT RESOURCE, CONNECT, CREATE ANY SYNONYM, UNLIMITED TABLESPACE TO TEST_USER;
RESOURCE, CONNECT, CREATE ANY SYNONYM, UNLIMITED TABLESPACE – are defined roles and privileges. These four units enough for creating a usable continuously growing Database. RESOURCE and CONNECT are roles and others are privileges;
TEST_USER is a ‘user-login’ to whom these roles and privileges were given.
If in some case you need to remove any of given roles or privileges:
REVOKE CREATE PUBLIC SYNONYM FROM TEST_USER;
CREATE PUBLIC SYNONYM – a defined privilege which has been deleted from the privilege list of the TEST_USER;
TEST_USER is a ‘user-login’ which lost defined privilege.
In the same way any Role given before is possible to be removed.