title: PLS-00201: identifier must be declared in Procedure
body: <p>I have a PL/SQL Procedure code, which runs when it is <code>/</code> , but doesn't runs when it's executed. The error message I get is </p>
  
  <pre><code>SQL&gt; EXECUTE MAXINUM;
  BEGIN MAXINUM; END;
  
        *
  ERROR at line 1:
  ORA-06550: line 1, column 7:
  PLS-00201: identifier 'MAXINUM' must be declared
  ORA-06550: line 1, column 7:
  PL/SQL: Statement ignored
  </code></pre>
  
  <p>The code which I'm working on is  :</p>
  
  <pre><code>DECLARE
      N NUMBER;
      M NUMBER;
      O NUMBER;
      P NUMBER;
      X NUMBER;
  PROCEDURE MAXINUM(N IN NUMBER, M IN NUMBER, O IN NUMBER, P IN NUMBER, X OUT NUMBER) IS
      BEGIN
      IF N&gt;M AND N&gt;O AND N&gt;P THEN
          X:=N;
      ELSIF M&gt;N AND M&gt;O AND M&gt;P THEN
          X:=M;
      ELSIF O&gt;N AND O&gt;M AND O&gt;P THEN
          X:=O;
      ELSIF P&gt;N AND P&gt;M AND P&gt;O  THEN
          X:=P;
      END IF;
      END;
  
  BEGIN
      N:=&amp;NUMBER;    
      M:=&amp;NUMBER;
      O:=&amp;NUMBER;
      P:=&amp;NUMBER;
      MAXINUM(N,M,O,P,X);
      DBMS_OUTPUT.PUT_LINE('HIGHEST NUMBER = '||X);
  END;
  /
  </code></pre>
  
  <p>When it gave the 'identifier error', I tried dropping this procedure I got the error:</p>
  
  <pre><code>SQL&gt; DROP PROCEDURE MAXINUM;
  DROP PROCEDURE MAXINUM
  *
  ERROR at line 1:
  ORA-04043: object MAXINUM does not exist
  </code></pre>
  
  <p>I have so far read <a href="https://stackoverflow.com/questions/29957063/error-pls-00201-identifier-must-be-declared">this</a>, <a href="https://stackoverflow.com/questions/32733197/oracle-pls-00201-identifier-vat-register-ap-vat-reg3-must-be-declared">this</a>, <a href="https://stackoverflow.com/questions/39718779/pls-00201-identifier-r-cur-must-be-declared-in-dynamic-sql">this</a> solutions and other solutions some what related to this error. </p>