discuz7里面的mysql类dbstuff

dz7安装目录/include/db_mysql.class.php：

class dbstuff {

  var $version = '';
  var $querynum = 0;
  var $link = null;

  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($sql);
    }

    $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);
  }

  function halt($message = '', $sql = '') {
    define('CACHE_FORBIDDEN', TRUE);
    require_once DISCUZ_ROOT.'./include/db_mysql_error.inc.php';
  }
}

因为用dz7,而且很多人估计也想了解这个论坛，或者二次开发，自己拿出来一点点的扣，呵呵。

1.select_db($dbname)方法选择数据库，实际是调用自带的

mysql_select_db函数，参数是要选择的数据库名字。

2.fetch_array($query, $result_type = MYSQL_ASSOC)

获取结果集的一条记录以某种形式数组返回，调用的也是自带的

mysql_fetch_array($query, $result_type)函数

3.fetch_first($sql)获取第一条记录，看看方法体

return $this->fetch_array($this->query($sql))

根据参数的sql语句，查询，而不是以$query句柄做参数，这样查第一条。

4.version()方法，返回version属性，mysql版本号，我本机的是这个：

5.1.30-community ，mysql5.1.30社区版。

虽然只是简单的封装了下，但是有必要了解下，对读dz的源码有帮助