class DPDO{
  private $DSN;
  private $DBUser;
  private $DBPwd;
  private $longLink;
  private $pdo;
  //私有构造函数 防止被直接实例化
  private function __construct($dsn, $DBUser, $DBPwd, $longLink = false) {
    $this->DSN = $dsn;
    $this->DBUser = $DBUser;
    $this->DBPwd = $DBPwd;
    $this->longLink = $longLink;
    $this->connect();
  }
  //私有 空克隆函数 防止被克隆
  private function __clone(){}
  //静态 实例化函数 返回一个pdo对象
  static public function instance($dsn, $DBUser, $DBPwd, $longLink = false){
    static $singleton = array();//静态函数 用于存储实例化对象
    $singIndex = md5($dsn . $DBUser . $DBPwd . $longLink);
    if (empty($singleton[$singIndex])) {
      $singleton[$singIndex] = new self($dsn, $DBUser, $DBPwd, $longLink = false);
    }
    return $singleton[$singIndex]->pdo;
  }
   
  private function connect(){
    try{
      if($this->longLink){
        $this->pdo = new PDO($this->DSN, $this->DBUser, $this->DBPwd, array(PDO::ATTR_PERSISTENT => true));
      }else{
        $this->pdo = new PDO($this->DSN, $this->DBUser, $this->DBPwd);
      }
      $this->pdo->query('SET NAMES UTF-8');
    } catch(PDOException $e) {
      die('Error:' . $e->getMessage() . '<br/>');
    }
  }
}

//字段关联数组处理， 主要用于写入和更新数据、同and 或 or 的查询条件，产生sql语句和映射字段的数组
  public function FDFields($data, $link = ',', $judge = array(), $aliasTable = ''){
    $sql = '';
    $mapData = array();
    foreach($data as $key => $value) {
      $mapIndex = ':' . ($link != ',' "htmlcode">

public function fetch($sql, $searchData = array(), $dataMode = PDO::FETCH_ASSOC, $preType = array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY)) {
    if ($sql) {
      $sql .= ' limit 1';
      $pdoStatement = $this->pdo->prepare($sql, $preType);
      $pdoStatement->execute($searchData);
      return $data = $pdoStatement->fetch($dataMode);
    } else {
      return false;
    }
  }
   
  public function fetchAll($sql, $searchData = array(), $limit = array(0, 10), $dataMode = PDO::FETCH_ASSOC, $preType = array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY)) {
    if ($sql) {
      $sql .= ' limit ' . (int) $limit[0] . ',' . (intval($limit[1]) > 0 "htmlcode">

header("Content-type: text/html; charset=utf-8");
define('APP_DIR', dirname(__FILE__));
 
if (function_exists('spl_autoload_register')) {
  spl_autoload_register('autoClass');
} else {
  function __auto_load($className){
    autoClass($className);
  }
}
 
function autoClass($className){
  try{
    require_once APP_DIR.'/class/'.$className.'.php';
  } catch (Exception $e) {
    die('Error:' . $e->getMessage() . '<br />');
  }
}
$DB = new DB();
//插入
$inData['a'] = rand(1, 100);
$inData['b'] = rand(1, 1000);
$inData['c'] = rand(1,200) . '.' . rand(1,100);
$ret = $DB->insert('a', $inData);
echo '插入' . ($ret ? '成功' : '失败') . '<br/>';
//更新
$upConData['a'] = 100;
$upConJudge['a'] = '<';
$upConData['b'] = 30;
$upConJudge['b'] = '>';
list($upConStr, $mapUpConData) = $DB->FDField('b', 200, '<', 'gt');
$condition = array(
  'str' => $upConStr,
  'data' => $upConData,
  'judge' => $upConJudge,
  'link' => 'and'
);
$upData['a'] = rand(1, 10);
$upData['b'] = 1;
$upData['c'] = 1.00;
$changeRows = $DB->update('a', $upData, $condition, $mapUpConData);
echo '更新行数:' . (int) $changeRows . '<br/>';
//删除
$delVal = rand(1, 10);
list($delCon, $mapDelCon) = $DB->FDField('a', $delVal);
$delRet = $DB->delete('a', $delCon, $mapDelCon);
echo '删除a=' . $delVal . ($delRet ? '成功' : '失败') . '<br/>';
 
//查询
$data['a'] = '10';
$judge['a'] = '>';
$data['b'] = '400';
$judge['b'] = '<';
list($conSql, $mapConData) = $DB->FDFields($data, 'and', $judge);
$mData = $DB->fetch('select * from a where ' . $conSql . ' order by `a` desc', $mapConData);
 
var_dump($mData);


以上所述就是本文的全部内容了，希望大家能够喜欢。