冒险村物语
英雄无敌3塔防
驾考家园手游

php实战第五天

2015-05-27

php单态设计模式，我的理解，类中创建静态变量，使其只有一个，使用方法进行返回对象，该方法检查对象是存在不存在就创建。从而实现单一对象。

将__construct()设置为private这样就new不了咯.self是本类的意思。“::”调用静态方法

[php] <?php
    /**
    *
    */
    class myclass
    {
        static private $db_class;
        static public function getClass()
        {
            if (is_null(self::$db_class)) {
                self::$db_class=new myclass();
                echo "创建对象咯";
            }else{
                echo "返回原来的对象";
                return self::$db_class;
            }
        }
        private function __construct()
        {
            echo "11111111111111";
        }

        public function __destruct(){
            echo "<br>aaaaaaaaaaaa";
        }
        public function show(){
            echo "bbbbbbbbbbbbbbb";
        }
    }
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a=myclass::getClass();
    $a->show();

    /*//直接new 会报错的噢!!!
    new myclass();
    new myclass();

    new myclass();
    new myclass();

    new myclass();
    new myclass();
    new myclass();
    new myclass();*/
?>

<?php
/**
*
*/
class myclass
{
  static private $db_class;
  static public function getClass()
  {
   if (is_null(self::$db_class)) {
    self::$db_class=new myclass();
    echo "创建对象咯";
   }else{
    echo "返回原来的对象";
    return self::$db_class;
   }
  }
  private function __construct()
  {
   echo "11111111111111";
  }

  public function __destruct(){
   echo "<br>aaaaaaaaaaaa";
  }
  public function show(){
   echo "bbbbbbbbbbbbbbb";
  }
}
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a=myclass::getClass();
$a->show();

/*//直接new 会报错的噢!!!
new myclass();
new myclass();

new myclass();
new myclass();

new myclass();
new myclass();
new myclass();
new myclass();*/
?>

这个是小例子.下面给出单态的 mysql类

[php] <?php
// +----------------------------------------------------------------------
// |MySQL操作类
// +----------------------------------------------------------------------
// |@微凉 QQ:496928838
// +----------------------------------------------------------------------
class MySQL{

    private $db_mysql_hostname;
    private $db_mysql_username;
    private $db_mysql_password;
    private $db_mysql_database;
    private $db_mysql_port;
    private $db_mysql_charset;

    private $query_list = array();

    //查询次数
    public $query_count = 0;
    //查询开始时间
    public $query_start_time;

    //当前查询ID
    protected $queryID;
    //当前连接
    protected $conn;
    // 事务指令数
    protected $transTimes = 0;
    // 返回或者影响记录数
    protected $numRows    = 0;
    // 错误信息
    protected $error      = '';

    //静态实例
    static private $db_class;
    //取得本类
    static public function getClass()
    {
      if (is_null(self::$db_class)) {
            self::$db_class=new MySQL();
        }
        return self::$db_class;
    }

    //定义为私有方法就new起来咯,要用 getClass
    private function __construct()
    {

    }

    public function connect($hostname_or_conf,$username,$password,$database,$port = '3306',$char = 'utf8'){
        if(is_array($hostname_or_conf)){
            $this->db_mysql_hostname = $hostname_or_conf['hostname'];
            $this->db_mysql_username = $hostname_or_conf['username'];
            $this->db_mysql_password = $hostname_or_conf['password'];
            $this->db_mysql_database = $hostname_or_conf['database'];
            $this->db_mysql_port = isset($hostname_or_conf['port'])?$hostname_or_conf['port']:'3306';
            $this->db_mysql_charset = isset($hostname_or_conf['charset'])?$hostname_or_conf['charset']:'utf8';
        }elseif(!empty($hostname_or_conf)||!empty($username)||!empty($password)||!empty($database))
        {
             $this->db_mysql_hostname = $hostname_or_conf;
             $this->db_mysql_username = $username;
             $this->db_mysql_password = $password;
             $this->db_mysql_database = $database;
             $this->db_mysql_port = $port;
             $this->db_mysql_charset = $char;

        }else{
            die('configuration error.');
        }

        $server = $this->db_mysql_hostname.':'.$this->db_mysql_port;
        $this->conn = mysql_connect($server,$this->db_mysql_username,$this->db_mysql_password,true) or die('Connect MySQL DB error!');
        mysql_select_db($this->db_mysql_database,$this->conn) or die('select db error!');
        mysql_query("set names " . $this->db_mysql_charset, $this->conn);

    }

    /**
     +----------------------------------------------------------
     * 设置数据对象值
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     *table,where,order,limit,data,field,join,group,having
     +----------------------------------------------------------
     */
    public function table($table){
        $this->query_list['table'] = $table;
        return $this;
    }

    public function where($where){
        $this->query_list['where'] = $where;
        return $this;
    }

    public function order($order){
        $this->query_list['order'] = $order;
        return $this;
    }

    public function limit($offset,$length=null){
        if (is_null($length)) {
            $this->query_list['limit']='limit '.$offset;
            return $this;
        }else {
            if(!isset($length)){
                $length = $offset;
                $offset = 0;
            }
                $this->query_list['limit'] = 'limit '.$offset.','.$length;
                return $this;
        }

    }

    public function data($data){
        //读取数据表字段,然后处理表单数据
        $dataList = $this->getFields($this->query_list['table']);
        $arr=array();
        foreach ($dataList as $key=>$value) {
            if (array_key_exists ($key,$data) ) {
                $arr[$key]=$data[$key];
            }

        }
        //var_dump($arr);
        /*
        if(is_object($data)){
            $data   =   get_object_vars($data);
        }elseif (is_string($data)){
            parse_str($data,$data);
        }elseif(!is_array($data)){
            //Log:DATA_TYPE_INVALID
        }
        */
        $this->query_list['data'] = $arr;
        return $this;
    }
    public function field($fields){
        $this->query_list['fields'] = $fields;
        return $this;
    }
    public function join($join){
        $this->query_list['join'] = $join;
        return $this;
    }
    public function group($group){
        $this->query_list['group'] = $group;
        return $this;
    }
    public function having($having){
        $this->query_list['having'] = $having;
        return $this;
    }
    /**
     +----------------------------------------------------------
     * 查询
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
    public function select(){
        $select_sql = 'select ';
        $fields = isset($this->query_list['fields'])?$this->query_list['fields']:'*';
        $select_sql.=$fields;
        $select_sql.= ' from `'.$this->query_list['table'].'` ';

        isset($this->query_list['join'])?($select_sql.=$this->query_list['join']):'';
        isset($this->query_list['where'])?($select_sql.=' where '.$this->query_list['where']):'';
        isset($this->query_list['group'])?($select_sql.=' group by'.$this->query_list['group']):'';
        isset($this->query_list['having'])?($select_sql.=' mysql having '.$this->query_list['having']):'';
        isset($this->query_list['order'])?($select_sql.=' order by '.$this->query_list['order']):'';
        isset($this->query_list['limit'])?($select_sql.=' '.$this->query_list['limit']):'';
    // echo '----->'.$select_sql;
        return $this->query($select_sql);
    }
    /**
     +----------------------------------------------------------
     * 增加
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
    public function add(){
        $add_sql = 'insert into `'.$this->query_list['table'].'` (';

        $data = $this->query_list['data'];
        $value = $field = '';
        foreach($data as $k=>$v){
            $field .= '`'.$k.'`,';
            if(is_numeric($v))
                $value .= $v.',';
            else
                $value .= '/''.$v.'/',';
        }
        $add_sql .= rtrim($field,',').') values ('.rtrim($value,',').')';

    // echo 'add_sql'.$add_sql;
        return $this->execute($add_sql);
    }
    /**
     +----------------------------------------------------------
     * 删除
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
    public function delete(){
        $del_sql = 'delete from `'.$this->query_list['table'].'` where '.$this->query_list['where'];

        if(isset($this->query_list['order']))
            $del_sql .= 'order by '.$this->query_list['order'];
        if(isset($this->query_list['limit']))
            $del_sql .= ' '.$this->query_list['limit'];

        return $this->execute($del_sql);

    }
    /**
     +----------------------------------------------------------
     * 更新
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
    public function update(){
        $update_sql = 'update `'.$this->query_list['table'].'` set ';
        $data = $this->query_list['data'];

        foreach($data as $k=>$v){
            if(is_numeric($v))
                $update_sql .= '`'.$k.'` ='.$v.',';
            else
                $update_sql .= '`'.$k.'` =/''.$v.'/',';
        }
        $update_sql = rtrim($update_sql,',');
        if(isset($this->query_list['where']))
            $update_sql .= ' where '.$this->query_list['where'];
        if(isset($this->query_list['order']))
            $update_sql .= ' order by '.$this->query_list['order'];
        if(isset($this->query_list['limit']))
            $update_sql .= ' '.$this->query_list['limit'];

        return $this->execute($update_sql);

    }
     /**
     +----------------------------------------------------------
     * 执行查询返回数据集
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param string $sql sql指令
     */
    public function query($sql) {
        if ( !$this->conn ) return false;
        $this->queryStr = $sql;
        //释放前次的查询结果
        if ( $this->queryID ) {    $this->free();    }

        $this->query_start_time = microtime(true);

        $this->queryID = mysql_query($sql, $this->conn);
        $this->query_count++;
        if ( false === $this->queryID ) {
            $this->error();
            return false;
        } else {
            $this->numRows = mysql_num_rows($this->queryID);
            return $this->getAll();
        }
    }
    /**
     +----------------------------------------------------------
     * 执行语句
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param string $sql sql指令
     +----------------------------------------------------------
     */
    public function execute($sql) {
        if ( !$this->conn ) return false;
        $this->queryStr = $sql;
        //释放前次的查询结果
        if ( $this->queryID ) {    $this->free();    }

        $this->query_start_time = microtime(true);

        $result =   mysql_query($sql, $this->conn) ;
        $this->query_count++;
        if ( false === $result) {
            $this->error();
            return false;
        } else {
            $this->numRows = mysql_affected_rows($this->conn);
            return $this->numRows;
        }
    }
    /**
     +----------------------------------------------------------
     * 获得所有的查询数据
     +----------------------------------------------------------
     * @access private
     +----------------------------------------------------------
     * @return array
     */
    private function getAll() {
        //返回数据集
        $result = array();
        if($this->numRows >0) {
            while($row = mysql_fetch_assoc($this->queryID)){
                $result[]   =   $row;
            }
            mysql_data_seek($this->queryID,0);
        }
        return $result;
    }
    /**
     +----------------------------------------------------------
     * 取得数据表的字段信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function getFields($tableName) {
        $result =   $this->query('SHOW COLUMNS FROM `'.$tableName.'`');
        $info   =   array();
        if($result) {
            foreach ($result as $key => $val) {
                $info[$val['Field']] = array(
                    'name'    => $val['Field'],
                    'type'    => $val['Type'],
                    'notnull' => (bool) ($val['Null'] === ''), // not null is empty, null is yes
                    'default' => $val['Default'],
                    'primary' => (strtolower($val['Key']) == 'pri'),
                    'autoinc' => (strtolower($val['Extra']) == 'auto_increment'),
                );
            }
        }
        return $info;
    }
    /**
     +----------------------------------------------------------
     * 取得数据库的表信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function getTables($dbName='') {
        if(!empty($dbName)) {
           $sql    = 'SHOW TABLES FROM '.$dbName;
        }else{
           $sql    = 'SHOW TABLES ';
        }
        $result =   $this->query($sql);
        $info   =   array();
        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }
        return $info;
    }

    /**
     +----------------------------------------------------------
     * 最后次操作的ID
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
     public function last_insert_id(){
        return mysql_insert_id($this->conn);
    }
    /**
     * 执行一条带有结果集计数的
     */
    public function count($sql){
        return $this->execute($sql);
    }
    /**
     +----------------------------------------------------------
     * 启动事务
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return void
     +----------------------------------------------------------
     */
    public function startTrans() {
        if ($this->transTimes == 0) {
            mysql_query('START TRANSACTION', $this->conn);
        }
        $this->transTimes++;
        return ;
    }

    /**
     +----------------------------------------------------------
     * 提交事务
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return boolen
     +----------------------------------------------------------
     */
    public function commit()
    {
        if ($this->transTimes > 0) {
            $result = mysql_query('COMMIT', $this->conn);
            $this->transTimes = 0;
            if(!$result){
                throw new Exception($this->error());
            }
        }
        return true;
    }

    /**
     +----------------------------------------------------------
     * 事务回滚
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return boolen
     +----------------------------------------------------------
     */
    public function rollback()
    {
        if ($this->transTimes > 0) {
            $result = mysql_query('ROLLBACK', $this->conn);
            $this->transTimes = 0;
            if(!$result){
                throw new Exception($this->error());
            }
        }
        return true;
    }
    /**
     +----------------------------------------------------------
     * 错误信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
     public function error() {
        $this->error = mysql_error($this->conn);
        if('' != $this->queryStr){
            $this->error .= "/n [ SQL语句 ] : ".$this->queryStr;
        }
        return $this->error;
    }
    /**
     +----------------------------------------------------------
     * 释放查询结果
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function free() {
        @mysql_free_result($this->queryID);
        $this->queryID = 0;
        $this->query_list = null;
    }
    /**
     +----------------------------------------------------------
     * 关闭连接
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
    function close(){
        if ($this->conn && !mysql_close($this->conn)){
            throw new Exception($this->error());
        }
        $this->conn = 0;
        $this->query_count = 0;
    }
    /**
     +----------------------------------------------------------
     * 析构方法
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    function __destruct(){
         $this->close();
    }
}

<?php
// +----------------------------------------------------------------------
// |MySQL操作类
// +----------------------------------------------------------------------
// |@微凉 QQ:496928838
// +----------------------------------------------------------------------
class MySQL{

private $db_mysql_hostname;
private $db_mysql_username;
private $db_mysql_password;
private $db_mysql_database;
private $db_mysql_port;
private $db_mysql_charset;

private $query_list = array();

//查询次数
public $query_count = 0;
//查询开始时间
public $query_start_time;

//当前查询ID
protected $queryID;
//当前连接
protected $conn;
// 事务指令数
protected $transTimes = 0;
// 返回或者影响记录数
    protected $numRows    = 0;
    // 错误信息
    protected $error      = '';

    //静态实例
    static private $db_class;
    //取得本类
    static public function getClass()
    {
      if (is_null(self::$db_class)) {
            self::$db_class=new MySQL();
        }
        return self::$db_class;
    }

    //定义为私有方法就new起来咯,要用 getClass
    private function __construct()
    {

    }

    public function connect($hostname_or_conf,$username,$password,$database,$port = '3306',$char = 'utf8'){
        if(is_array($hostname_or_conf)){
            $this->db_mysql_hostname = $hostname_or_conf['hostname'];
            $this->db_mysql_username = $hostname_or_conf['username'];
            $this->db_mysql_password = $hostname_or_conf['password'];
            $this->db_mysql_database = $hostname_or_conf['database'];
            $this->db_mysql_port = isset($hostname_or_conf['port'])?$hostname_or_conf['port']:'3306';
            $this->db_mysql_charset = isset($hostname_or_conf['charset'])?$hostname_or_conf['charset']:'utf8';
        }elseif(!empty($hostname_or_conf)||!empty($username)||!empty($password)||!empty($database))
        {
             $this->db_mysql_hostname = $hostname_or_conf;
             $this->db_mysql_username = $username;
             $this->db_mysql_password = $password;
             $this->db_mysql_database = $database;
             $this->db_mysql_port = $port;
             $this->db_mysql_charset = $char;

        }else{
            die('configuration error.');
        }

        $server = $this->db_mysql_hostname.':'.$this->db_mysql_port;
        $this->conn = mysql_connect($server,$this->db_mysql_username,$this->db_mysql_password,true) or die('Connect MySQL DB error!');
        mysql_select_db($this->db_mysql_database,$this->conn) or die('select db error!');
        mysql_query("set names " . $this->db_mysql_charset, $this->conn);

}

/**
     +----------------------------------------------------------
     * 设置数据对象值
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     *table,where,order,limit,data,field,join,group,having
     +----------------------------------------------------------
     */
public function table($table){
  $this->query_list['table'] = $table;
  return $this;
}

public function where($where){
  $this->query_list['where'] = $where;
  return $this;
}

public function order($order){
  $this->query_list['order'] = $order;
  return $this;
}

public function limit($offset,$length=null){
  if (is_null($length)) {
   $this->query_list['limit']='limit '.$offset;
   return $this;
  }else {
   if(!isset($length)){
    $length = $offset;
    $offset = 0;
   }
    $this->query_list['limit'] = 'limit '.$offset.','.$length;
    return $this;
  }

}

public function data($data){
  //读取数据表字段,然后处理表单数据
  $dataList = $this->getFields($this->query_list['table']);
  $arr=array();
  foreach ($dataList as $key=>$value) {
   if (array_key_exists ($key,$data) ) {
    $arr[$key]=$data[$key];
   }

  }
  //var_dump($arr);
  /*
  if(is_object($data)){
   $data   =   get_object_vars($data);
  }elseif (is_string($data)){
   parse_str($data,$data);
  }elseif(!is_array($data)){
   //Log:DATA_TYPE_INVALID
  }
  */
  $this->query_list['data'] = $arr;
  return $this;
}
public function field($fields){
  $this->query_list['fields'] = $fields;
  return $this;
}
public function join($join){
  $this->query_list['join'] = $join;
  return $this;
}
public function group($group){
  $this->query_list['group'] = $group;
  return $this;
}
public function having($having){
  $this->query_list['having'] = $having;
  return $this;
}
/**
     +----------------------------------------------------------
     * 查询
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function select(){
  $select_sql = 'select ';
  $fields = isset($this->query_list['fields'])?$this->query_list['fields']:'*';
  $select_sql.=$fields;
  $select_sql.= ' from `'.$this->query_list['table'].'` ';

  isset($this->query_list['join'])?($select_sql.=$this->query_list['join']):'';
  isset($this->query_list['where'])?($select_sql.=' where '.$this->query_list['where']):'';
  isset($this->query_list['group'])?($select_sql.=' group by'.$this->query_list['group']):'';
  isset($this->query_list['having'])?($select_sql.=' mysql having '.$this->query_list['having']):'';
  isset($this->query_list['order'])?($select_sql.=' order by '.$this->query_list['order']):'';
  isset($this->query_list['limit'])?($select_sql.=' '.$this->query_list['limit']):'';
// echo '----->'.$select_sql;
  return $this->query($select_sql);
}
/**
     +----------------------------------------------------------
     * 增加
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function add(){
  $add_sql = 'insert into `'.$this->query_list['table'].'` (';

  $data = $this->query_list['data'];
  $value = $field = '';
  foreach($data as $k=>$v){
   $field .= '`'.$k.'`,';
   if(is_numeric($v))
    $value .= $v.',';
   else
    $value .= '/''.$v.'/',';
  }
  $add_sql .= rtrim($field,',').') values ('.rtrim($value,',').')';

// echo 'add_sql'.$add_sql;
  return $this->execute($add_sql);
}
/**
     +----------------------------------------------------------
     * 删除
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function delete(){
  $del_sql = 'delete from `'.$this->query_list['table'].'` where '.$this->query_list['where'];

  if(isset($this->query_list['order']))
   $del_sql .= 'order by '.$this->query_list['order'];
  if(isset($this->query_list['limit']))
   $del_sql .= ' '.$this->query_list['limit'];

  return $this->execute($del_sql);

}
/**
     +----------------------------------------------------------
     * 更新
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function update(){
  $update_sql = 'update `'.$this->query_list['table'].'` set ';
  $data = $this->query_list['data'];

  foreach($data as $k=>$v){
   if(is_numeric($v))
    $update_sql .= '`'.$k.'` ='.$v.',';
   else
    $update_sql .= '`'.$k.'` =/''.$v.'/',';
  }
  $update_sql = rtrim($update_sql,',');
  if(isset($this->query_list['where']))
   $update_sql .= ' where '.$this->query_list['where'];
  if(isset($this->query_list['order']))
   $update_sql .= ' order by '.$this->query_list['order'];
  if(isset($this->query_list['limit']))
   $update_sql .= ' '.$this->query_list['limit'];

  return $this->execute($update_sql);

}
/**
     +----------------------------------------------------------
     * 执行查询返回数据集
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param string $sql sql指令
     */
    public function query($sql) {
        if ( !$this->conn ) return false;
        $this->queryStr = $sql;
        //释放前次的查询结果
        if ( $this->queryID ) {    $this->free();    }

        $this->query_start_time = microtime(true);

        $this->queryID = mysql_query($sql, $this->conn);
        $this->query_count++;
        if ( false === $this->queryID ) {
            $this->error();
            return false;
        } else {
            $this->numRows = mysql_num_rows($this->queryID);
            return $this->getAll();
        }
    }
/**
     +----------------------------------------------------------
     * 执行语句
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param string $sql sql指令
     +----------------------------------------------------------
     */
    public function execute($sql) {
        if ( !$this->conn ) return false;
        $this->queryStr = $sql;
        //释放前次的查询结果
        if ( $this->queryID ) {    $this->free();    }

        $this->query_start_time = microtime(true);

        $result =   mysql_query($sql, $this->conn) ;
        $this->query_count++;
        if ( false === $result) {
            $this->error();
            return false;
        } else {
            $this->numRows = mysql_affected_rows($this->conn);
            return $this->numRows;
        }
    }
/**
     +----------------------------------------------------------
     * 获得所有的查询数据
     +----------------------------------------------------------
     * @access private
     +----------------------------------------------------------
     * @return array
     */
    private function getAll() {
        //返回数据集
        $result = array();
        if($this->numRows >0) {
            while($row = mysql_fetch_assoc($this->queryID)){
                $result[]   =   $row;
            }
            mysql_data_seek($this->queryID,0);
        }
        return $result;
    }
/**
     +----------------------------------------------------------
     * 取得数据表的字段信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function getFields($tableName) {
        $result =   $this->query('SHOW COLUMNS FROM `'.$tableName.'`');
        $info   =   array();
        if($result) {
            foreach ($result as $key => $val) {
                $info[$val['Field']] = array(
                    'name'    => $val['Field'],
                    'type'    => $val['Type'],
                    'notnull' => (bool) ($val['Null'] === ''), // not null is empty, null is yes
                    'default' => $val['Default'],
                    'primary' => (strtolower($val['Key']) == 'pri'),
                    'autoinc' => (strtolower($val['Extra']) == 'auto_increment'),
                );
            }
        }
        return $info;
    }
/**
     +----------------------------------------------------------
     * 取得数据库的表信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function getTables($dbName='') {
        if(!empty($dbName)) {
           $sql    = 'SHOW TABLES FROM '.$dbName;
        }else{
           $sql    = 'SHOW TABLES ';
        }
        $result =   $this->query($sql);
        $info   =   array();
        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }
        return $info;
    }

/**
     +----------------------------------------------------------
     * 最后次操作的ID
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function last_insert_id(){
        return mysql_insert_id($this->conn);
    }
    /**
     * 执行一条带有结果集计数的
     */
    public function count($sql){
        return $this->execute($sql);
    }
/**
     +----------------------------------------------------------
     * 启动事务
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return void
     +----------------------------------------------------------
     */
    public function startTrans() {
        if ($this->transTimes == 0) {
            mysql_query('START TRANSACTION', $this->conn);
        }
        $this->transTimes++;
        return ;
    }

    /**
     +----------------------------------------------------------
     * 提交事务
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return boolen
     +----------------------------------------------------------
     */
    public function commit()
    {
        if ($this->transTimes > 0) {
            $result = mysql_query('COMMIT', $this->conn);
            $this->transTimes = 0;
            if(!$result){
                throw new Exception($this->error());
            }
        }
        return true;
    }

    /**
     +----------------------------------------------------------
     * 事务回滚
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @return boolen
     +----------------------------------------------------------
     */
    public function rollback()
    {
        if ($this->transTimes > 0) {
            $result = mysql_query('ROLLBACK', $this->conn);
            $this->transTimes = 0;
            if(!$result){
                throw new Exception($this->error());
            }
        }
        return true;
    }
/**
     +----------------------------------------------------------
     * 错误信息
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
public function error() {
        $this->error = mysql_error($this->conn);
        if('' != $this->queryStr){
            $this->error .= "/n [ SQL语句 ] : ".$this->queryStr;
        }
        return $this->error;
    }
/**
     +----------------------------------------------------------
     * 释放查询结果
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
    public function free() {
        @mysql_free_result($this->queryID);
        $this->queryID = 0;
        $this->query_list = null;
    }
    /**
     +----------------------------------------------------------
     * 关闭连接
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     * @param
     +----------------------------------------------------------
     */
function close(){
  if ($this->conn && !mysql_close($this->conn)){
            throw new Exception($this->error());
        }
        $this->conn = 0;
        $this->query_count = 0;
}
/**
     +----------------------------------------------------------
     * 析构方法
     +----------------------------------------------------------
     * @access public
     +----------------------------------------------------------
     */
function __destruct(){
   $this->close();
}
}