title: Unable to drop default constraint in Oracle
body: <pre><code>SQL&gt; ALTER TABLE CUSTOMERS MODIFY AGE INT DEFAULT 10;
  </code></pre>
  
  <p>Table altered.</p>
  
  <pre><code>SQL &gt; ALTER TABLE CUSTOMERS ALTER COLUMN AGE DROP DEFAULT;
  
  ERROR at line 2:
  ORA - 01735 : invalid ALTER TABLE OPTION.
  </code></pre>