php中PDO方式实现数据库的增删改查

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,$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($dsn,$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->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 != ',' ? 'c' : '') . $aliasTable . $key;
      $sql .= ' ' . ($aliasTable ? $aliasTable . '.' : '') . '`' . $key . '` ' . ($judge[$key] ? $judge[$key] : '=') . ' ' . $mapIndex . ' ' . $link;
      $mapData[$mapIndex] = $value;
    }
    $sql = trim($sql,$link);
    return array($sql,$mapData);
  }
  //用于处理单个字段处理
  public function FDField($field,$value,$judge = '=',$preMap = 'cn',$aliasTable = '') {
    $mapIndex = ':' . $preMap . $aliasTable . $field;
    $sql = ' ' . ($aliasTable ? $aliasTable . '.' : '') . '`' . $field . '`' . $judge . $mapIndex;
    $mapData[$mapIndex] = $value;
    return array($sql,$mapData);
  }
  //使用刚办法可以便捷产生查询条件及对应数据数组
  public function FDCondition($condition,$mapData) {
    if(is_string($condition)) {
        $where = $condition;
    } else if (is_array($condition)) {
      if($condition['str']) {
        if (is_string($condition['str'])) {
          $where = $condition['str'];
        } else {
          return false;
        }
      }
      if(is_array($condition['data'])) {
        $link = $condition['link'] ? $condition['link'] : 'and';
        list($conSql,$mapConData) = $this->FDFields($condition['data'],$link,$condition['judge']);
        if ($conSql) {
          $where .= ($where ? ' ' . $link : '') . $conSql;
          $mapData = array_merge($mapData,$mapConData);
        }
      }
    }
    return array($where,$mapData);
  }

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($sql,$limit = array(0,10),$preType = array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY)) {
    if ($sql) {
      $sql .= ' limit ' . (int) $limit[0] . ',' . (intval($limit[1]) > 0 ? intval($limit[1]) : 10);
      $pdoStatement = $this->pdo->prepare($sql,$preType);
      $pdoStatement->execute($searchData);
      return $data = $pdoStatement->fetchAll($dataMode);
    } else {
      return false;
    }
  }
   
  public function insert($tableName,$data,$returnInsertId = false,$replace = false) {
    if(!empty($tableName) && count($data) > 0){
      $sql = $replace ? 'REPLACE INTO ' : 'INSERT INTO ';
      list($setSql,$mapData) = $this->FDFields($data);
      $sql .= $tableName . ' set ' . $setSql;
      $pdoStatement = $this->pdo->prepare($sql,array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet ? ($returnInsertId ? $this->pdo->lastInsertId() : $execRet) : false;
    } else {
      return false;
    }
  }
   
  public function update($tableName,$condition,$mapData = array(),$returnRowCount = true) {
    if(!empty($tableName) && count($data) > 0) {
      $sql = 'UPDATE ' . $tableName . ' SET ';
      list($setSql,$mapSetData) = $this->FDFields($data);
      $sql .= $setSql;
      $mapData = array_merge($mapData,$mapSetData);
      list($where,$mapData) = $this->FDCondition($condition,$mapData);
      $sql .= $where ? ' WHERE ' . $where : '';
      $pdoStatement = $this->pdo->prepare($sql,array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet ? ($returnRowCount ? $pdoStatement->rowCount() : $execRet) : false;
    } else {
      return false;
    }
  }
   
  public function delete($tableName,$mapData = array()) {
    if(!empty($tableName) && $condition){
      $sql = 'DELETE FROM ' . $tableName;
      list($where,array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
      $execRet = $pdoStatement->execute($mapData);
      return $execRet;
    }
  }

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,$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);