PHP独立Session数据库存储操作类分享

直接上代码：
代码如下:
class DbSession
{

    const TYPE_INT = 1;
    const TYPE_STR = 2;

    /**
     * Database configration
     *
     * @var array
     */
    private $_config = array(
            ‘host' => '127.0.0.1′,
            ‘port' => 3306,
            ‘username' => ‘root',
            ‘password' => ‘root',
            ‘dbname' => ‘db_mylab',
        ‘tablename' => ‘t_sessions',
        ‘cookie_prefix' => ‘mylab_',
        ‘cookiepath' => ‘/',
        ‘cookiedomain' => ”,
        ‘cookie_timeout' => 900
    );

    /**
     * Table fields type array
     *
     * @var array
     */
    private  $_db_fields = array(
        ‘crc32sid'      => self::TYPE_INT,
                ‘sessionhash'   => self::TYPE_STR,
                ‘idhash'        => self::TYPE_STR,
                ‘userid'        => self::TYPE_INT,
                ‘ipaddress'     => self::TYPE_STR,
                ‘lastactivity'  => self::TYPE_STR,
                ‘location'      => self::TYPE_STR,
        ‘loggedin'      => self::TYPE_INT,
        ‘heartbeat'     => self::TYPE_STR
        );

        /**
         * db obj
         *
         * @var mysqli object