title: varchar2(n BYTE|CHAR) default -> CHAR or BYTE
body: <p>I am supporting code that has below schema declaration:-</p>
  
  <pre><code>create table sample (
          id number Primary key,
          username varchar2(100),
  );
  </code></pre>
  
  <p>I looked up on Oracle documentation &amp; varchar2 has two declaration modes
  varchar2(n BYTE) and varchar2(n CHAR), If I don't specify explicitly BYTE or CHAR
  &amp; just declare username varchar2(500) then will 500 BYTES be allocated or 500 characters?</p>
  
  <p>thanks,</p>