title: PDO with self signed certificates
body: <p>I'm still tryin to connect with PDO to a remote MySQL database. Customer provide self signed certificates, <code>client-key.pem</code> and <code>client-cert.pem</code>. Certificates are good, I can connect to remote db using mysql client.
  This is where I instantiate a PDO object to connect to db.</p>
  
  <pre><code>pdoDb = new PDO(
    'mysql:host=customer_host_name;dbname=customer_db_name', 
    'my_username', 
    'my_password', 
    array(
     PDO::MYSQL_ATTR_SSL_KEY=&gt;'C:/Apache24/htdocs/CLIENT/lib/client-key.pem',
     PDO::MYSQL_ATTR_SSL_CERT=&gt;'C:/Apache24/htdocs/CLIENT/lib/client-cert.pem'
    ));
  </code></pre>
  
  <p>I'm getting this error when I instantiate PDO object:</p>
  
  <pre><code>Warning: PDO::__construct(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:ssl3_get_server_certificate:certificate verify failed in C:\Apache24\htdocs\CUSTOMER\lib\database.php on line 17
  </code></pre>
  
  <p>I think code was correct but I'm newbie to PHP.</p>
  
  <p><strong><em>Update</em></strong>
  Pardon me. I forgot to mention that I didn't specify a value for  <code>MYSQL_ATTR_SSL_CA</code> because customer doesn't give me one. Sorry. Is <code>MYSQL_ATTR_SSL_CA</code> mandatory to <code>PDO</code> (or <code>mysqli</code>)?</p>