php实现的pdo公共类定义与用法示例

本文实例讲述了php实现的pdo公共类定义与用法。分享给大家供大家参考，具体如下：db.class.

本文实例讲述了php实现的pdo公共类定义与用法。分享给大家供大家参考，具体如下：

db.class.php ：

<?php
class db extends \PDO {
 private static $_instance = null;
 protected $dbName = '';
 protected $dsn;
 protected $dbh;
 public function __construct($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset='utf8') {
 try {
 $this->dsn = 'mysql:host=' . $dbHost . ';dbname=' . $dbName;
 $this->dbh = new \PDO($this->dsn, $dbUser, $dbPasswd);
 $this->dbh->setAttribute(\PDO::ATTR_EMULATE_PREPARES, false);
 $this->dbh->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
 $this->dbh->exec('SET character_set_connection='.$dbCharset.';SET character_set_client='.$dbCharset.';SET character_set_results='.$dbCharset);
 } catch (Exception $e) {
 $this->outputError($e->getMessage()); 
 }
 }
 public static function getInstance($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset='utf8') {
 if (self::$_instance === null) {
 self::$_instance = new self($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset);
 }
 return self::$_instance;
 }
 public function fetchAll($sql, $params = array()) {
 try {
 $stm = $this->dbh->prepare($sql);
 if ($stm && $stm->execute($params)) {
 return $stm->fetchAll(\PDO::FETCH_ASSOC);
 }
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function fetchOne($sql, $params = array()) {
 try {
 $result = false;
 $stm = $this->dbh->prepare($sql);
 if ($stm && $stm->execute($params)) {
 $result = $stm->fetch(\PDO::FETCH_ASSOC);
 }
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function fetchColumn($sql, $params = array()) {
 $result = '';
 try {
 $stm = $this->dbh->prepare($sql);
 if ($stm && $stm->execute($params)) {
 $result = $stm->fetchColumn();
 }
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function insert($table, $params = array(), $returnLastId = true) {
 $_implode_field = '';
 $fields = array_keys($params);
 $_implode_field = implode(',', $fields);
 $_implode_value = '';
 foreach ($fields as $value) {
 $_implode_value .= ':'. $value.',';
 }
 $_implode_value = trim($_implode_value, ',');
 $sql = 'INSERT INTO ' . $table . '(' . $_implode_field . ') VALUES ('.$_implode_value.')';
 try {
 $stm = $this->dbh->prepare($sql);
 $result = $stm->execute($params);
 if ( $returnLastId ) {
 $result = $this->dbh->lastInsertId();
 }
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function update($table, $params = array(), $where = null) {
 $_implode_field = '';
 $_implode_field_arr = array();
 if ( empty($where) ) {
 return false;
 }
 $fields = array_keys($params);
 foreach ($fields as $key) {
 $_implode_field_arr[] = $key . '=' . ':'.$key;
 }
 $_implode_field = implode(',', $_implode_field_arr);
 $sql = 'UPDATE ' . $table . ' SET ' . $_implode_field . ' WHERE ' . $where;
 try {
 $stm = $this->dbh->prepare($sql);
 $result = $stm->execute($params);
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function delete($sql, $params = array()) {
 try {
 $stm = $this->dbh->prepare($sql);
 $result = $stm->execute($params);
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 public function exec($sql, $params = array()) {
 try {
 $stm = $this->dbh->prepare($sql);
 $result = $stm->execute($params);
 return $result;
 } catch (Exception $e) {
 $this->outputError($e->getMessage());
 }
 }
 private function outputError($strErrMsg) {
 throw new Exception("MySQL Error: " . $strErrMsg);
 }
 public function __destruct() {
 $this->dbh = null;
 }
}

实例：

<?php
require_once './db.class.php';
$pdo = db::getInstance('127.0.0.1', 'root', '111111', 'php_cms');
$sql = "select id, title1 from cms_wz where id = :id limit 1";
$parame = array('id' => 12,);
$res = $pdo->fetchOne($sql, $parame);
var_dump($res);
$sql = 'SELECT * FROM cms_link';
$result = $db->fetchAll($sql);
print_r($result);
//查询记录数量
$sql = 'SELECT COUNT(*) FROM cms_link';
$count = $db->fetchColumn($sql);
echo $count;
$data = array(
 'siteid' => 1,
 'linktype' => 1,
 'name' => 'google',
 'url' => 'http://www.google.com',
 'listorder' => 0,
 'elite' => 0,
 'passed' => 1,
 'addtime' => time()
 );
$lastInsertId = $db->insert('cms_link', $data);
echo $lastInsertId;
//用 try
 try {
 $result = $pdo->insert('news', $essay);
 } catch (Exception $e) {
 error_log($e->getMessage());
 error_log($e->getMessage() . ' in ' . __FILE__ . ' on line ' . __LINE__);
 saveLog('url文章 : ' . $essay['link'] . ' 数据插入失败<br>');
 continue;
 }
$data = array(
 'siteid' => 1,
 'linktype' => 1,
 'name' => 'google',
 'url' => 'http://www.google.com',
 'listorder' => 0,
 'elite' => 0,
 'passed' => 1,
 'addtime' => time()
 );
$db->insert('cms_link', $data);
$sql = 'DELETE FROM cms_link WHERE linkid=4';
$result = $db->delete($sql);
var_dump($result);