title: Difference between VARCHAR2(10 CHAR) and NVARCHAR2(10)
body: <p>I've installed Oracle Database 10g Express Edition (Universal) with the default settings:</p>
  <pre><code>SELECT * FROM NLS_DATABASE_PARAMETERS;
  </code></pre>
  <pre class="lang-none prettyprint-override"><code>NLS_CHARACTERSET               AL32UTF8                                 
  NLS_NCHAR_CHARACTERSET         AL16UTF16                                
  </code></pre>
  <p>Given that both <code>CHAR</code> and <code>NCHAR</code> data types seem to accept multi-byte strings, what is the exact difference between these two column definitions?</p>
  <pre><code>VARCHAR2(10 CHAR)
  NVARCHAR2(10)
  </code></pre>