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
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:' . $e->getMessage() . '
');
}
}
}用于处理字段映射，使用pdo的字段映射，可以有效避免sql注入
//字段关联数组处理， 主要用于写入和更新数据、同and 或 or 的查询条件，产生sql语句和映射字段的数组
public function FDFields($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, $mapData);
}增删改查的具体实现DB.php
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public function fetch($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, $replace = false) {
if(!empty($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, $data, $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, $condition, $mapData = array()) {
if(!empty($tableName) && $condition){
$sql = 'DELETE FROM ' . $tableName;
list($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 $execRet;
}
}测试文件test.php
header("Content-type: text/html; charset=utf-8");
define('APP_DIR', dirname(FILE));
if (function_exists('spl_autoload_register')) {
spl_autoload_register('autoClass');
} else {
function auto_load($className){
autoClass($className);
}
}
function autoClass($className){
try{
require_once APP_DIR.'/class/'.$className.'.php';
} catch (Exception $e) {
die('Error:' . $e->getMessage() . '
');
}
}
$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') . '
';
//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 . '
';
//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') . '
';
//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); 
