Can We Force a User to Run a Script When Connecting to the Server?

There is a system level AFTER LOGON ON DATABASE trigger that can be incorporated into your database code. The trigger is executed after the user logon is processed. A trigger body can contain PL/SQL code.

Inside the trigger you have access to the username via sys_context so you can conditionally execute code if you desire.

Oracle 10g Documentation here

Here is a basic example:

CREATE OR REPLACE TRIGGER LOGON_TEST
AFTER LOGON ON DATABASE
BEGIN

  -- Your custom code here
  -- Use SYS_CONTEXT() to get information about the user's session
  -- Ex: sys_context('USERENV','SESSION_USER')

END;
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