title: How to catch a unique constraint error in a PL/SQL block?
body: <p>Say I have an Oracle PL/SQL block that inserts a record into a table and need to recover from a unique constraint error, like this:</p>
  
  <pre><code>begin
      insert into some_table ('some', 'values');
  exception
      when ...
          update some_table set value = 'values' where key = 'some';
  end;
  </code></pre>
  
  <p>Is it possible to replace the ellipsis for something in order to catch an unique constraint error?</p>