title: How do I find all the functional indexes on a column in Oracle
body: <p>Say I have a program that searches a database for columns to modify, as part of a database conversion process.</p>
  
  <p>If I attempt to alter a column with a functional index defined gives the following error:</p>
  
  <pre><code>ORA-30556: functional index is defined on the column to be modified
  </code></pre>
  
  <p><a href="http://ora-30556.ora-code.com/" rel="noreferrer">Looking up the ORA code</a>, the solution is to "Drop the functional index before attempting to modify the column."</p>
  
  <p>Great!  So how do I find all the functional indexes on that column?  </p>
  
  <p>The <code>user_ind_columns</code> view looks like a good start, but functional indexes have things like "SYS_NC00042$" in their <code>COLUMN</code> column.  Looking around the other <code>user_</code> views, I'm not seeing anything obvious.  Am I missing something?</p>
  
  <p>Or am I going about this the wrong way entirely?</p>