Step by Step Create read only user in oracle

Step1:

[oravis@qb ~]$ sqlplus / as sysdba

SQL> Create user db_admin identified by db_admin

         default tablespace APPS_TS_TX_DATA

         temporary tablespace temp

         quota 0M on APPS_TS_TX_DATA;

         User created.

Step2:

SQL>  Create role r_role;

          Grant create session to r_role;

          Grant connect to r_role;

          Grant select any table to r_role;

          Grant execute any procedure to r_role;

          Grant create trigger to r_role;

          Role created.

Step3:

SQL> Grant r_role to qlik;

         Grant succeeded.

Step4:

SQL> conn db_admin/db_admin;

          Connected.

Step5:

SQL>  Create trigger rlogin_trigger

           After logon on db_admin.schema

           Begin

           Execute immediate 'Alter session set current_schema = apps';

           End;  

           Trigger created.

Step6:

SQL>  Revoke create trigger from r_role;

           Revoke succeeded.