my first php mysql class

<?php
class db
{
	var $querynum = 0;
	var $link;
    var $histories;
    var $dbhost;
    var $dbuser;
    var $dbpw;
    var $dbcharset;
    var $pconnect;
    var $tablepre;
    var $time;
    var $goneaway = 5;
    function connect($dbhost, $dbuser, $dbpw, $dbname = '', $dbcharset = '', $pconnect = 0, $tablepre='', $time = 0)
    {
        $this->dbhost = $dbhost;
        $this->dbuser = $dbuser;
        $this->dbpw = $dbpw;
        $this->dbname = $dbname;
        $this->dbcharset = $dbcharset;
        $this->pconnect = $pconnect;
        $this->tablepre = $tablepre;
        $this->time = $time;
		
        if($pconnect)
        {
            if(!$this->link = mysql_pconnect($dbhost, $dbuser, $dbpw))
            {
                $this->halt('Can not connect to MySQL server');
            }
        }
        else
        {
            if(!$this->link = mysql_connect($dbhost, $dbuser, $dbpw))
            {
                $this->halt('Can not connect to MySQL server');
            }
        }
        if($this->version() > '4.1')
        {
            if($dbcharset)
            {
                mysql_query("SET character_set_connection = ".$dbcharset.", 
                                    character_set_results = ".$dbcharset.", 
                                     character_set_client = binary", $this->link);
            }

            if($this->version() > '5.0.1') {
                mysql_query("SET sql_mode =''", $this->link);
            }
        }
        if($dbname)
        {
            mysql_select_db($dbname, $this->link);
        }
    }
    function fetch_array($query, $result_type = MYSQL_ASSOC)
    {
        return mysql_fetch_array($query, $result_type);
    }
    function result_first($sql)
    {
        $query = $this->query($sql);
        return $this->result($query, 0);
    }
    function fetch_first($sql)
    {
        $query = $this->query($sql);
        return $this->fetch_array($query);
    }
    function fetch_all($sql, $id = '')
    {
        $arr = array();
        $query = $this->query($sql);
        while($data = $this->fetch_array($query))
        {
            $id ? $arr[$data[$id]] = $data : $arr[] = $data;
        }
        return $arr;
    }
    function cache_gc()
    {
        $this->query("DELETE FROM {$this->tablepre}sqlcaches WHERE expiry<$this->time");
    }
    function query($sql, $type = '', $cachetime = FALSE)
    {
        $func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ? 'mysql_unbuffered_query' : 'mysql_query';
        if(!($query = $func($sql, $this->link)) && $type != 'SILENT')
        {
            $this->halt('MySQL Query Error', $sql);
        }
        $this->querynum++;
        $this->histories[] = $sql;
        return $query;
    }
    
   function result($query, $row)
    {
        $query = @mysql_result($query, $row);
        return $query;
    }
    
    function affected_rows()
    {
        return mysql_affected_rows($this->link);
    }

    function error()
    {
        return (($this->link) ? mysql_error($this->link) : mysql_error());
    }
    function errno()
    {
        return intval(($this->link) ? mysql_errno($this->link) : mysql_errno());
    }
 
    function num_rows($query)
    {
        $query = mysql_num_rows($query);
        return $query;
    }
    function num_fields($query)
    {
        return mysql_num_fields($query);
    }

    function free_result($query)
    {
        return mysql_free_result($query);
    }

    function insert_id()
    {
        return ($id = mysql_insert_id($this->link)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
    }

    function fetch_row($query)
    {
        echo $query;
        $query = mysql_fetch_row($query);
        return $query;
    }

    function fetch_fields($query)
    {
        return mysql_fetch_field($query);
    }

    function version()
    {
        return mysql_get_server_info($this->link);
    }

    function close()
    {
        return mysql_close($this->link);
    }

    function halt($message = '', $sql = '')
    {
        $error = mysql_error();
        $errorno = mysql_errno();
        if($errorno == 2006 && $this->goneaway-- > 0)
        {
            $this->connect($this->dbhost, $this->dbuser, $this->dbpw, $this->dbname, $this->dbcharset, $this->pconnect, $this->tablepre, $this->time);
            $this->query($sql);
        }
        else
        {
            $s = '<b>Error:</b>'.$error.'<br />';
            $s .= '<b>Errno:</b>'.$errorno.'<br />';
            $s .= '<b>SQL:</b>:'.$sql;
            exit($s);
        }
    }
}

?>