title: Insert record into oracle after defining virtual column
body: <p>So I noticed that after defining a virtual column in oracle I wasn't able to insert without mentioning specific column name. Is there any documentation about this?</p>
  
  <p>eg:- Without defining a Virtual Column, the following works:</p>
  
  <pre><code>INSERT INTO film VALUES ('12F', 'Full Screen', 2015);
  </code></pre>
  
  <p>However, once I define a virtual column called number (which stores the number part from number_key) like the following:</p>
  
  <pre><code>ALTER TABLE film ADD (number AS (substr(number_key,1,2)));
  </code></pre>
  
  <p>I am unable to add the records using the above insert statement, I get an error:</p>
  
  <pre><code> SQL Error: ORA-00947: not enough values
   00947. 00000 -  "not enough values"
  </code></pre>
  
  <p>I have to explicitly qualify the column names in my insert queries. Why is that the case? Am I mising something here.</p>