php 超级强大的数据库连接类

function connect($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0, $halt = TRUE, $dbcharset2 = '') {

  $func = empty($pconnect) ? 'mysql_connect' : 'mysql_pconnect';
  if(!$this->link = @$func($dbhost, $dbuser, $dbpw, 1)) {
   $halt && $this->halt('Can not connect to MySQL server');
  } else {
   if($this->version() > '4.1') {
    global $charset, $dbcharset;
    $dbcharset = $dbcharset2 ? $dbcharset2 : $dbcharset;
    $dbcharset = !$dbcharset && in_array(strtolower($charset), array('gbk', 'big5', 'utf-8')) ? str_replace('-', '', $charset) : $dbcharset;
    $serverset = $dbcharset ? 'character_set_connection='.$dbcharset.', character_set_results='.$dbcharset.', character_set_client=binary' : '';
    $serverset .= $this->version() > '5.0.1' ? ((empty($serverset) ? '' : ',').'sql_mode=\'\'') : '';
    $serverset && mysql_query("SET $serverset", $this->link);
   }
   $dbname && @mysql_select_db($dbname, $this->link);
  }

 }

 function select_db($dbname) {
  return mysql_select_db($dbname, $this->link);
 }

 function fetch_array($query, $result_type = MYSQL_ASSOC) {
  return mysql_fetch_array($query, $result_type);
 }

 function fetch_first($sql) {
  return $this->fetch_array($this->query($sql));
 }

 function result_first($sql) {
  return $this->result($this->query($sql), 0);
 }

 function query($sql, $type = '') {

  global $debug, $discuz_starttime, $sqldebug, $sqlspenttimes;

  if(defined('SYS_DEBUG') && SYS_DEBUG) {
   @include_once DISCUZ_ROOT.'./include/debug.func.php';
   sqldebug();
  }

  $func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
   'mysql_unbuffered_query' : 'mysql_query';
  if(!($query = $func($sql, $this->link))) {
   if(in_array($this->errno(), array(2006, 2013)) && substr($type, 0, 5) != 'RETRY') {
    $this->close();
    require DISCUZ_ROOT.'./config.inc.php';
    $this->connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect, true, $dbcharset);
    $this->query($sql, 'RETRY'.$type);
   } elseif($type != 'SILENT' && substr($type, 5) != 'SILENT') {
    $this->halt('MySQL Query Error', $sql);
   }
  }

  $this->querynum++;
  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 result($query, $row = 0) {
  $query = @mysql_result($query, $row);
  return $query;
 }

 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) {
  $query = mysql_fetch_row($query);
  return $query;
 }

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

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

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