PDO是mysql数据库操作的一个公用类了，我们不需要进行自定类就可以直接使用pdo来操作数据库了，但是在php默认配置中pdo是未开启所以我们必须先在php.ini中开启它才可以使用。

　　需要开启php的pdo支持，php5.1以上版本支持

　　实现数据库连接单例化，有三要素 静态变量、静态实例化方法、私有构造函数 DPDO.php

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 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/>'); } } }

　　用于处理字段映射，使用pdo的字段映射，可以有效避免sql注入

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 //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, $mapData); } //使用刚方法可以便捷产生查询条件及对应数据数组 public function FDCondition($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); }

　　增删改查的具体实现DB.php

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 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 ? 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(!e