title: CodeIgniter - how to post value from form as NULL instead of 0
body: <p>In my database it is a table: <em>tab_companies</em> and a column <em>company_phone</em> (big integer) with defalut value set to NULL.</p>
  
  <p>When somebody fill the form and will leave the <em>phone number</em> field empty Code Igniter should add a NULL value to the database, but instead I am having always value '0'.</p>
  
  <pre><code>public function add_company()
  {
      $data = array(
          'company_short-name'        =&gt; $this-&gt;input-&gt;post('company_short-name'),
          'company_full-name'         =&gt; $this-&gt;input-&gt;post('company_full-name'),
          'company_phone'             =&gt; $this-&gt;input-&gt;post('company_phone'),
          'company_address'           =&gt; $this-&gt;input-&gt;post('company_address'),
      );
  
      return $this-&gt;db-&gt;insert('tab_companies', $data);   
  }
  </code></pre>
  
  <p>What I am doing wrong?</p>