title: SQL Server: Null VS Empty String
body: <p>How are the <code>NULL</code> and <em>Empty Varchar</em> values stored in <em>SQL Server</em>. And in case I have no user entry for a <code>string</code> field on my <em>UI</em>, should I store a <code>NULL</code> or a <code>''</code> ?</p>