Simple PL/SQL script to alter parameter in database

At my current workplace, we use emcli for mass-updates of database parameters in groups of databases.

Below is a simple PL/SQL script that can be used to change parameter if needed. If the parameter is already set, nothing happens.

In my case, it was the parameter "recyclebin" that was needed to be switched from OFF to ON for some databases, but it could be any parameter.

Surely there are many ways to solve such a problem, this was how I solved it with very little effort :-)

set serveroutput on
set feedback off
set echo off
set verify off

DECLARE

 v_db_name v$database.name%%TYPE;
 v_rb v$system_parameter.name%%TYPE;


BEGIN
 execute immediate 'alter session set nls_language=''american''';
 select name
 into v_db_name
 from v$database;

 select value
 into v_rb
 from v$system_parameter
 where name = 'recyclebin';
 
--dbms_output.put_line('v_db_name: ' || v_db_name);
--dbms_output.put_line('v_rb:      ' || v_rb);

CASE
   WHEN v_rb = 'ON' THEN
    dbms_output.put_line('Database ' || v_db_name || ': recyclebin already enabled.');
   ELSE
    dbms_output.put_line('Database ' || v_db_name || ': recyclebin is currently disabled. Turning it on now...');
    execute immediate 'alter system set recyclebin=ON scope=spfile';
     dbms_output.put_line('Database ' || v_db_name || ' now has recyclebin=ON in spfile. Database must be bounced in in order to enable the setting');
   END CASE;
END;
/
exit

When we execute the script through emcli, the syntax comes to:

emcli execute_sql -sql="FILE" -iemcli execute_sql -sql="FILE" -input_file="FILE:/scripts/chk_and_alter_param.sql" -targets="TEST_DBS:composite"