1、fetch_all
 DB::fetch_all(sql, $arg = array());//取出符合条件的所有数据
 sql为查询语句，$arg为绑定参数
 例：$result = DB::fetch_all(\'SELECT * FROM %t\',array(\'table_name\'));
 $result为二维数组
2、fetch_first
 DB::fetch_first(sql, $arg = array());//取出符合条件的第一条数据
 例：$result = DB::fetch_first(\'SELECT * FROM %t \', array(\'table_name\'));
 $result为一维数组

DB::insert(参数一,参数二,参数三);
 /*
 参数一：table_name
 参数二：以对应数据表中的字段为key，具体数值为value组成的关联数组
 参数三：是否返回该数据的id。true则返回具体id，false则不会返回id
 */
 例：DB::insert(\'table_name\',[\'name\'=>\'张三\',\'age\'=>\'18\',\'sex\'=>\'男\'],true);

DB::update(参数一,参数二,参数三);
 /*
 参数一：table_name
 参数二：以对应数据表中的字段为key，具体数值为value组成的关联数组
 参数三：修改的where条件
 */
 例：DB::update(\'table_name\',[\'name\'=>\'张三\',\'age\'=>\'19\',\'sex\'=>\'男\'],\' id = 1 \');

 DB::delete(参数一,参数二);
 /*
 参数一：table_name
 参数二：删除的where条件
 */
 例：$sql = \'id = \'.$id;
 DB::delete(\'table_name\',$sql);

table_forum_design_list.php
<?php
/**
 *      [Discuz!] (C)2001-2099 Comsenz Inc.
 *      This is NOT a freeware, use is subject to license terms
 *
 *      $Id: table_forum_access.php 27777 2012-02-14 07:07:26Z zhengqingpeng $
 */
if(!defined(\'IN_DISCUZ\')) {
    exit(\'Access Denied\');
}

class table_forum_design_list extends discuz_table
{
    public function __construct() {

    $this->_table = \'forum_design_list\';
    $this->_pk    = \'\';

    parent::__construct();
    }


    public function get_all() {
    return DB::fetch_all(\'SELECT * FROM %t WHERE st != 0\', array($this->_table));
    }
    public function insert($data)
    {
        return DB::insert($this->_table,$data,true);
    }
    public function delete($id)
    {
        $sql = \'id = \'.$id;
        return DB::delete($this->_table,$sql);
    }
}
?>
//外部文件调用方式
$result = C::t(\'forum_design_list\')->get_all();
$result = C::t(\'forum_design_list\')->insert($data);
$result = C::t(\'forum_design_list\')->delete(1);

DB::query(sql,$arg = array());