<?php

/**

+----------------------

 * Mysql操作类

+----------------------

 * 文件名称  Db.class.php

+----------------------

 * 文件描述  mysql操作类

+----------------------

 */

class Db{

    //数据库连接标识

    protected $link = null;

    //当前操作的表

    public $table = '';

    //查询参数

    protected $options = array();

    //当前执行的SQL语句

    protected $sql = '';

    //用什么编码传递数据

    protected $dbCharset = 'utf8';



    //缓存路径

    protected $cachePath = './cache/';

    //缓存扩展名

    protected $cacheFileExt = "php";

    //缓存文件名

    protected $cacheFileName;

    //是否缓存

    protected $cache = false;

    //缓存更新时间秒数

    protected $cacheLimitTime = 60;



    //数据返回类型, 1代表数组, 2代表对象

    protected $returnType = 1;



  /*

   * 根据当前动态文件生成缓存文件名

   */

	function setCacheFileName($fileName) {

		$cacheFileName = $this->cachePath . strtoupper(md5($fileName)).".".$this->cacheFileExt;

		$this->cacheFileName=$cacheFileName;

    }

  /*

   * 根据当前动态文件生成缓存文件名

   */

	function getCacheFileName() {

		return  $this->cacheFileName;

    }

    /**

     * 连接数据库

     *

     * @access      public

     * @param       array    $db  数据库配置

     * @return      resource 数据库连接标识

     */

    public function connect($db){

        //根据配置使用不同函数连接数据库

        $db['host'] = isset($db['port']) ? $db['host'].':'.$db['port']: $db['host'];

        $db['char'] = isset($db['char']) ? $db['char']: $this->dbCharset;

        $func = $db['pconnect'] ? 'mysql_pconnect' : 'mysql_connect';

        $this->link = $func($db['host'], $db['user'], $db['pwd']);

        mysql_select_db($db['database'], $this->link);

        mysql_query("SET NAMES '{$db['char']}'");

        $this->cachePath = isset($db['cachepath']) ? $db['cachepath']: $this->cachePath;

        return $this->link;

    }

    /**

     * 查询符合条件的一条记录

     *

     * @access      public

     * @param       string    $where  查询条件

     * @param       string    $field  查询字段

     * @param       string    $table  表

     * @return      mixed             符合条件的记录

     */

    public function find($where = NULL, $field = '*', $table = ''){

        return $this->findAll($where = NULL, $field = '*', $table = '', FALSE);

    }

    /**

     * 查询符合条件的所有记录

     *

     * @access      public

     * @param       string    $where  查询条件

     * @param       string    $field  查询字段

     * @param       string    $table  表

     * @return      mixed             符合条件的记录

     */

    public function findAll($where = NULL, $field = '*', $table = '', $all = TRUE){

        $this->options['where'] = is_null($where) ? @$this->options['where']: $where;

        $this->options['field'] = isset($this->options['field']) ? $this->options['field']: $field;

        $this->options['table'] = $table == '' ? $this->table: $table;

        $sql = "SELECT {$this->options['field']} FROM `{$this->options['table']}` ";

        $sql .= isset($this->options['join']) ? ' LEFT JOIN '.$this->options['join']: '';

        $sql .= isset($this->options['where']) ? ' WHERE '.$this->options['where']: '';

        $sql .= isset($this->options['group']) ? ' GROUP BY '.$this->options['group']: '';

        $sql .= isset($this->options['having']) ? ' HAVING '.$this->options['having']: '';

        $sql .= isset($this->options['order']) ? ' ORDER BY '.$this->options['order']: '';

        $sql .= isset($this->options['limit']) ? ' LIMIT '.$this->options['limit']: '';

        $this->sql = $sql;

        $row = NULL;

        //如果开启了缓存, 那么重缓存中获取数据

        if ($this->cache === TRUE){

			$this->setCacheFileName($this->sql);

            $row = $this->readCache();

        }

        //如果读取失败, 或则没有开启缓存

        if (is_null($row)){

            $result = $this->query();

            $row = $all === TRUE ? $this->fetchAll($result): $this->fetch($result);

            //如果开启了缓存, 那