SP2-0552: Bind Variable "NEW" is not declared
<p>I am trying to learn pl/sql triggers. I am trying to create a simple trigger by tracking tutorial <a href="http://www.tutorialspoint.com/plsql/plsql_triggers.htm" rel="nofollow noreferrer">http://www.tutorialspoint.com/plsql/plsql_triggers.htm</a> but I got below error. I searched on the internet but could not find the solution. Could you help me on this issue?</p>

<pre><code>CREATE OR replace TRIGGER display_salary_changes 
  BEFORE DELETE OR INSERT OR UPDATE ON ok.customers 
  FOR EACH ROW 
DECLARE 
    sal_diff NUMBER; 
BEGIN 
    sal_diff := :NEW.salary - :OLD.salary; 
END; 
/ 


Trıgger DISPLAY_SALARY_CHANGES created.

SP2-0552: Bind Variable "NEW" is not declared.

PL/SQL procedure successfully completed.
</code></pre>

<p>Edit: I am using Sql Developer Version 4.1.1</p>

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