classes/SQL.php
public static function connect($dsn, $username=null, $password=null, $options=[]){
    return self::register('default', $dsn, $username, $password, $options);
  }
public static function connect($dsn, $username=null, $password=null, $options=[]){
    return self::register('default', $dsn, $username, $password, $options);
  }
public static function connect ( $ dsn , $ username = null , $ password = null , $ options = [ ] ) { return self :: register ( 'default' , $ dsn , $ username , $ password , $ options ) ; }
Register the default datasource
@param  string $dsn      PDO DSN URL
@param  string $username User credentials
@param  string $password User credentials
@param  array  $options  Options to pass to the PDO constructor
@return SQLConnection    The datasource resource
Register the default datasource