title: Why do I get an error as I try to call a procedure?
body: <p>I created a procedure named <em>greet</em> as :</p>
  
  <pre><code>create procedure greet(message in char(50))
  as  
  begin 
    dbms_output.put_line('Greet Message : ' || message);
  end;
  </code></pre>
  
  <p>The procedure compiled successfully but when I try to call it as :</p>
  
  <pre><code>execute greet('Hey ! This is a self created procedure :)');
  </code></pre>
  
  <p>I get an error :</p>
  
  <pre><code>execute greet('Hey ! This is a self created procedure :)')
  Error report:
  ORA-06550: line 1, column 7:  
  PLS-00905: object SUHAIL.GREET is invalid
  ORA-06550: line 1, column 7:
  PL/SQL: Statement ignored
  06550. 00000 -  "line %s, column %s:\n%s"
  *Cause:    Usually a PL/SQL compilation error.
  *Action:
  </code></pre>
  
  <p>What error is it ? Why do I get it ?</p>
  
  <p><em>Note : 'suhail' is name of the current user connected to oracle server</em></p>