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.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 => 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 =>

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　　希望本文所述对大家PHP程序设计有所帮助。