title: Using pdo_dblib to connect to the sybase failed
body: <p>I want to use PDO to connect to a Sybase using PHP <code>pdo_dblib</code>. This is what I have done:</p>
  
  <pre><code>$conn = new PDO("dblib:host=$db_host:$db_port;dbname=$db_name","$login","$password"); 
  </code></pre>
  
  <p>It shows me <code>SQL Null error</code>. I don't know how to get it right. I have checked the php info, and the pdo_dblib is there.</p>
  
  <pre><code>PDO Driver for FreeTDS/Sybase DB-lib: Flavour
  enabled: freetds
  </code></pre>
  
  <p>by the way, is the database port needed? Before this, I didn't put the database port number, plus now I'm still unable to get the port number.</p>